Trim size
Trim size is the finished width × height of a printed book's pages — 6×9 in is the most common self-publishing trim. Your interior PDF's pages must match the trim exactly.
Full definition →Reference
Glossary
Plain-English definitions of the Word styles, spacing, alignment, and formatting concepts behind cleaning up a document, from heading styles to APA and MLA format. Open any term for the full definition and related tools.
Gutter
The gutter is the extra inside margin next to a book's spine, added because binding swallows part of the page. Required gutter grows with page count — on KDP from 0.375" (≤150 pages) to 0.875" (828 pages).
Full definition →Recto and verso
Recto is the right-hand page of an open book (odd page numbers); verso is the left (even). Trade convention opens chapters on the recto, inserting a blank verso when needed.
Full definition →Running head
A running head is the line of text at the top of a book page — conventionally the author's name on the verso (left) and the book or chapter title on the recto (right). It is omitted on chapter openers and blank pages.
Full definition →Drop cap
A drop cap is an enlarged first letter that 'drops' into the opening lines of a chapter — typically 2–3 lines tall — signaling a beginning with typographic ceremony.
Full definition →Folio
In book design, the folio is the printed page number. A 'drop folio' sits at the foot of the page — the convention for chapter openers even when other pages carry numbers in the running head.
Full definition →Scene break
A scene break is a visual pause inside a chapter — marked in manuscripts as *** or a blank-line gap, and typeset as white space or an ornament (❦, ⁂, · · ·) with the next paragraph unindented.
Full definition →Widows and orphans
A widow is a paragraph's last line stranded at the top of a page; an orphan is a first line left alone at the bottom. Professional typesetting prevents both by adjusting page breaks.
Full definition →EPUB
EPUB is the open ebook format accepted by every major store — Amazon KDP, Apple Books, Kobo. A valid EPUB3 contains per-chapter files, a navigation table of contents, and metadata.
Full definition →Bleed
Bleed is printing past the trim line (usually 0.125") so ink reaches the page edge after trimming. Text-only book interiors don't need bleed; full-page images do.
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