fill-in /ˈfɪlˌɪn/noun 8fill in verb 5forms 4 noun8 •A temporary replacement for another, especially at a job.He went in to the Calsag bar to wrangle two fill-ins for the Goldenhoys as ordered. — 2012 •A substitution.All our language is loose: whatever one means to say, all words are fill-ins for other words - as any cursory glance at a dictionary reveals. — 2004 •A musical embellishment (usually percussion) that is added to connect musical phrases.The following abbreviations are used for all drum solos and fill-ins. — 2005 •Something added to fill a gap.With too many fill-ins the statistical results become dubious. — 1992 •Something added to increase the size of something; padding or filler.There was, at that time, a small film producing complex known as Ben Blake Studios where a variety of trailers, commercials, fill-ins, and (yes) screen tests were shot. — 2001 •A product category that is used to complete a range or variety of a product line.Since consumer buying behaviour to obtain staples is different from fill-ins, retailers strategy will also differ. — 2009 •A question or puzzle in which one is expected to fill in a missing part of something.The main interaction styles supported by Web systems are direct manipulation, menus and form fill-ins. — 2003 •An intermediate result that must be stored temporarily during the course of a sparse matrix computation.When a fill-in, aᵢⱼ⁽ˢ⁾ is created in the course of the computation, it may be necessary to make copies of the contents of certain parts of the ALU and CNLU at the ends of these arrays. — 1991 fill in verb5 •To fill; to replace material that is absent or has been removed.After you're done laying the pipe, fill in the trench. •(UK) To complete a form or questionnaire with requested information.I've got a form that is to be filled in in ink. •To inform somebody, especially to supply someone missing or missed information.If you know anything about this, maybe you can fill me in. •To substitute for somebody or something.He can't go on vacation very often because there is nobody to fill in for him. •(slang) To beat up; to physically assault.Talk to me like that again and I'll fill you in! formsfilled in · filling in · fills in · fill-ins