Filed from 3 published puzzles

VARIABLE

Set to 3 different clues across 3 published puzzles, most often “In the answers to 17-, 34- and 57-Across, it was replaced in turn by 1, 2, 3, 4, 5 ...” — The New York Times, Thursday, 11 August 2011.

8 letters

Every clue on record, most used first