Fill-in

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
 * 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