- AcroForm
- The interactive form technology built into the PDF standard. When a PDF has "real" fillable fields. The kind you can click and type into without any special tool, those fields are almost always AcroForm fields, with a name, type, and position defined directly in the PDF file itself.
- AcroForm widget
- A single on-page box belonging to a form field. One logical field can own several widgets. On a four-copy tax form, the payer name field has four, one per copy. Counting widgets tells you how many boxes are on the page; counting fields tells you how many facts the form needs.
- Addendum
- A supplementary document that modifies or adds to a main agreement (like a purchase agreement) without rewriting the whole thing. Closing packets often include several, each repeating key facts from the original agreement.
- BAA (Business Associate Agreement)
- A legal agreement required under HIPAA between a healthcare organization and any vendor that handles protected health information on its behalf. Relevant here because it affects which cloud services a tool is allowed to route sensitive documents through.
- Bidirectional sync (live two-way editor)
- An editing pattern where changing a value in one view (say, a list of fields) instantly updates every matching spot in another view (say, the document itself), and vice versa. Distinct from a one-way autofill, where filling a list only pushes values into the document, with no way to edit directly on the document and have it reflect back.
- Bracket placeholder
- A blank represented as bracketed text inside a document, like
[Buyer Full Name], instead of a blank line or underscore. Common in templates drafted in word processors before being exported to PDF.
- Certificate-based signature
- A signature backed by a certificate issued by a certificate authority, embedded in the PDF along with a cryptographic hash of the document. Opening the file later shows whether it was altered after signing, and who signed it. Different in kind from an e-signature, which is a mark on the page. Some documents specifically require one; most do not.
- Closing packet
- The full set of documents needed to complete a real estate transaction. Typically the purchase agreement, disclosures, addenda, and a settlement statement, usually 6 to 15 separate PDFs that share most of the same underlying facts.
- Code 128 (barcode)
- A barcode standard that encodes any printable ASCII text. Letters, digits, and symbols, as a pattern of bars. Widely used for SKUs, order numbers, and asset tags because it handles alphanumeric values, unlike simpler numeric-only formats. It includes a built-in check character so a misread scan is detected rather than silently returning the wrong value.
- Column clustering
- Grouping numbers into columns by their horizontal position on the page, since a PDF stores no table structure. It works when a generator aligns its columns and fails when one pads with spaces instead, which is why a good parser verifies its reading against the arithmetic rather than trusting position alone.
- Crop box
- The rectangle of a page a viewer displays, which can be smaller than the page itself. Cropping sets this rectangle; the content outside it remains in the file. That makes cropping reversible, and means it is not a substitute for redaction.
- Daily ending balance row
- A line some banks interleave inside the transaction table showing the account balance at the end of a day. It carries a date and an amount and is aligned exactly like a transaction, so nothing about its shape distinguishes it. Only its wording. Counting one as a transaction adds a phantom entry worth the whole account balance.
- Deal Vault
- A saved set of facts about one transaction (buyer, seller, property, key dates) that can be applied across every document in that transaction's packet, instead of being re-entered separately for each document.
- Delimiter
- The character separating columns in tabular text. Copying from a spreadsheet gives tab-separated values; a saved CSV file gives comma-separated ones. Detecting which is in use is the first step in reading pasted data correctly. A tool that assumes commas will mangle a spreadsheet paste containing addresses.
- Die-cut
- The physical pre-cut outline of each label on a label sheet. Printing is "aligned" when the printed content sits inside these cuts; when it doesn't, text straddles the boundary between two labels and the sheet is wasted. Getting this right is the entire technical challenge of label printing.
- Disclosure
- A document in which a seller states known facts about a property (condition issues, past repairs, environmental hazards) that a buyer is legally entitled to know before completing a purchase.
- Escrow
- A neutral third-party arrangement that holds funds and documents during a transaction until agreed-upon conditions are met, then releases them accordingly. The company managing this is usually called the escrow or title company.
- ESIGN Act and UETA
- The federal Electronic Signatures in Global and National Commerce Act, and the Uniform Electronic Transactions Act adopted by most states. Together they make an electronic signature as enforceable as ink for most agreements, provided the signer intended to sign and consented to doing it electronically. Some categories are carved out, including wills and certain notices, so a document that names a required signature method should be read rather than assumed.
- E-signature
- A signature captured through software rather than pen and paper. Under the ESIGN Act and UETA it is enough for most everyday agreements in the United States. It is not the same thing as a certificate-based signature, which binds a mark to a verified identity. Filling text fields and capturing a signature are separate technical problems, but they are not separate jobs: most documents that need one need the other on the same pass.
- Field character limit
- A maximum length defined on a PDF form field, commonly two characters for a state code. Text longer than the limit is rejected or silently truncated, so a tool filling the field should either warn or show the limit rather than letting the value disappear.
- Field clustering
- The process of recognizing that multiple blanks across a document (or packet) refer to the same underlying fact, and grouping them into a single field that can be filled once. The core technical problem behind automatic repeated-field detection, and one where being too aggressive merges fields that only look alike. PDFeyes now leaves the grouping to the person filling the form: one answer, placed by hand wherever it belongs, is a cluster with no guessing in it.
- Flatten (a PDF)
- To convert a filled interactive form into a fixed, non-editable version where the entered values are now a permanent part of the page content rather than editable field data. Most finished documents are flattened before being sent or filed, so the answers can't be accidentally changed later.
- Lossless operation
- A change that copies pages rather than re-rendering them, so text stays selectable and images keep their original quality. Merging, splitting, rotating and reordering are lossless; anything that rasterises a page is not.
- Mail merge
- The traditional word-processor feature for combining a document template with rows of data to produce many personalised copies. Capable but heavyweight: it requires linking a data source and inserting merge fields through a multi-step wizard, which is disproportionate effort for a recurring twenty-row job.
- Media box
- The full physical size of a PDF page, as opposed to the crop box that determines what is shown. A page can have a Letter-sized media box and a much smaller crop box.
- Multi-copy form
- A single PDF containing several versions of the same form for different recipients. Copy A for the IRS, Copy B for the recipient, and so on. The copies carry different marginal instructions but identical data, so any difference between them is an error.
- Notary signing agent
- A notary public who specializes in overseeing the signing of loan and real estate closing documents, often traveling to meet signers in person. A single closing appointment can involve dozens of pages requiring initials or signatures.
- OCR (Optical Character Recognition)
- Technology that analyzes a scanned image of a document and reconstructs the text it contains, along with an approximation of where each piece of text sits on the page. Required to do anything text-based (search, select, detect a blank) with a scanned PDF, since scanned documents have no real text data on their own, see the guide on scanned vs. Digital PDFs.
- Page rotation
- A property stored on a page telling viewers how far to turn it before display. Because it is a flag rather than a redraw, rotating is instant and lossless, though some printer drivers ignore it, which is why a rotated page can still print the wrong way up.
- Page tree
- The internal structure listing a PDF's pages in order. Merging, splitting, reordering and deleting all work by rewriting this list rather than touching the pages themselves, which is why those operations are lossless and fast.
- PDF encryption
- The standard's built-in password protection, covering both opening a document and permission to print or copy from it. It requires real cryptography rather than page manipulation, which is why many browser-based tools cannot add or remove it.
- PII (Personally Identifiable Information)
- Any information that could identify a specific person. Name, address, date of birth, ID numbers, and similar. Closing packets, HR paperwork, and immigration forms are almost entirely made up of PII, which is why data handling and encryption matter more here than in a typical document tool.
- Placeholder (field)
- Any spot in a document meant to be filled in. Whether it's an interactive AcroForm field, a blank line of underscores, bracketed text, or a label followed by empty space. Detecting all four styles reliably is harder than detecting just one, which is why many tools only handle the interactive-field case well.
- Point (typographic)
- A unit equal to 1/72 of an inch. PDF uses points internally for all positioning, which is why print-accurate layout work is best done in points directly. Converting through other units introduces rounding drift that accumulates across a page.
- Print scaling
- A printer or PDF viewer setting that resizes a document to fit the paper, commonly labeled "Fit to page" or "Shrink oversized pages." It is the most frequent cause of misaligned label sheets, because it shrinks the whole grid by a percent or two. Barely visible on the first label, obviously wrong by the bottom of the page. Setting it to 100% or "Actual size" fixes most alignment problems.
- Quiet zone
- The blank margin required on each side of a barcode for a scanner to find where the symbol starts and ends. Crowding a barcode against other content or the edge of a label is a common reason an otherwise correct barcode will not scan.
- Redaction
- Removing content from a document so it cannot be recovered. Drawing a black box over text is not redaction: the text is still in the file and any reader can extract it, which is how redacted court filings have leaked names. Real redaction either deletes the underlying content or re-renders the page as an image with the box burned in. PDFeyes does the second, which is why a redacted page comes back as a picture rather than selectable text.
- Reconciliation
- Checking that a set of transactions agrees with the balances recorded alongside them. On a bank statement with a running balance, each transaction amount should equal the difference between consecutive balances. Arithmetic the bank already performed, which can be used to automatically verify that a statement was read correctly and flag rows that don't add up.
- Reconciliation check
- Verifying that each transaction amount equals the difference between consecutive running balances. Because the bank already performed this arithmetic and printed it, the check is a genuine proof rather than a heuristic: it catches misread digits, inverted signs, dropped rows, and phantom rows in one pass.
- Running balance
- The account balance after each transaction, shown as its own column on many bank statements. Beyond being informative, it makes a statement self-checking: the differences between consecutive balances must match the transaction amounts, so it can be used to detect misread rows and to determine whether an ambiguous amount was a debit or a credit.
- Shrink to fit
- Reducing text size automatically until it fits inside a fixed area, used on labels where the content varies in length but the label does not. Distinct from print scaling, which shrinks an entire page and is the usual cause of misaligned label sheets.
- Sign convention
- How a statement indicates money leaving the account. Five are in common use: a leading minus, parentheses, a trailing minus, a DR/CR marker, or no marker at all with the direction implied by which column the number sits in. The last is the most error-prone, since the number itself carries no clue.
- Structured data
- Information organized in a predictable, machine-readable format (like a named field with a known type) as opposed to unstructured data (like a photo of a page). A PDF's AcroForm fields are structured; the pixels of a scanned page are not, until OCR extracts structure from them.
- Text layer
- The actual character data embedded in a digital PDF, distinct from how the page visually renders. A PDF has a usable text layer if you can select and copy text from it normally; a scanned PDF has no text layer at all unless OCR has been run on it to create one.
- Text run
- A single string of characters placed at one position inside a PDF. A run does not correspond to a table cell: a generator may emit an entire row as one run, or split a single word across several. This is why extracting a table from a PDF is inference rather than reading.
- Title company
- A company that verifies a property's legal ownership history, issues title insurance, and often manages the closing process and escrow funds for a real estate transaction.
- Transaction coordinator
- A professional (often working for a real estate brokerage or independently) who manages the paperwork and deadlines of a real estate transaction from contract to closing, including assembling and completing the closing packet.
- TSV (tab-separated values)
- Tabular data where columns are separated by tab characters. This is what lands on the clipboard when you copy cells from Excel, Google Sheets, or Numbers, which is why pasting spreadsheet data into a text field works at all.
- Title block
- The boxed strip on a drawing sheet, usually down the right-hand edge or along the bottom, carrying the sheet number, sheet title, project name, scale, issue date and the designer’s details. It is the only place on the sheet where the number is authoritative, which is why automatic naming reads it rather than scanning the whole page.
- Sheet number
- The identifier printed on each drawing, such as A-101 or S-201. Under the US National CAD Standard it is a discipline letter, then a digit for the type of drawing, then a sequence. A-201 is the second architectural elevation; S-101 is the first structural plan.
- Discipline designator
- The letter or letters at the start of a sheet number identifying the trade: A architectural, S structural, M mechanical, E electrical, P plumbing, C civil, G general. Two-letter designators such as FP for fire protection are common. It is how a set is filed and how a subcontractor finds their sheets.
- Drawing set
- The complete collection of sheets for a project, issued together and usually distributed as a single PDF. A full commercial set runs to hundreds of sheets across every discipline, which is why the individual sheet number matters more than the file name.
- Detail callout
- A reference printed on a drawing pointing to a detail elsewhere in the set, written as something like 3/A-501, meaning detail 3 on sheet A-501. It looks exactly like a sheet number and appears all over a floor plan, which is the main reason automatic sheet naming goes wrong.
- Issued for construction
- The status stamped on a drawing set released to build from, abbreviated IFC. Earlier issues are for pricing, permit or coordination. Splitting and distributing the wrong issue is a more expensive mistake than not splitting at all.
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