Definitions:

1. Refers to a typeset version of a publication, typically a book or a magazine, that is printed for review and correction before final printing. NOUN
   • The galley proof revealed a formatting error that would have disrupted the book's readability.
2. The stage in the publishing process where authors, editors, and proofreaders can review the layout, formatting, and content of the publication to identify any errors or make necessary revisions. NOUN
   • The author appreciated the opportunity to review the galley proof before the book went to print.

Synonyms:

• blueprint
• page proof
• plate proof
• pre-press proof
• press proof
• proof image
• test copy
• trial print