ZOIC

Set to 3 different clues across 5 published puzzles, most often “Suffix on era names” — The New York Times, Sunday, 31 January 2010.

4 letters

Every clue on record, most used first

Suffix on era names3 times
The New York Times — Sunday, 31 January 2010
Suffix with Meso- or Paleo-once
The New York Times — Wednesday, 30 April 2008
Suffix in the names of many erasonce
The New York Times — Saturday, 14 December 2002