What is "fill-in"

"substitute," 1918 (as an adjective, 1916), from verbal phrase; see fill (v.), in (adv.). Earlier as a noun was fill-up (1811).

n. A temporary replacement for another

n. someone who takes the place of another (as when things get dangerous or difficult); "the star had a stand-in for dangerous scenes"; "we need extra employees for summer fill-ins" [syn: stand-in, substitute, relief, reliever, backup, backup man]

Fill-in can refer to:

• A puzzle, see Fill-In (puzzle)
• In numerical analysis, the entries of a matrix which change from zero to a non-zero value in the execution of an algorithm; see Sparse matrix#Reducing fill-in
• An issue of a comic book produced by a different creative team than the one regularly assigned to the series, published either to avoid missing a deadline or to give one or more of the series's regular creators a break

Fill-Ins, also known as Fill-It-Ins or Word Fills, are a variation of the common crossword puzzle in which words, rather than clues, are given. Fill-Ins are common in puzzle magazines along with word searches, cryptograms, and other logic puzzles. Some consider Fill-Ins to be an easier version of the crossword. Since the Fill-In requires no outside knowledge of specific subjects, one can solve the puzzle in another language.

Solving a Fill-In usually requires trial-and-error. Many times, a first word is already given to help the solver start, but some difficult puzzles require the solver to begin from scratch without any help. Word entries are listed alphabetically by amount of letters.