Home Dee Dee Word of the Day – Dec. 14 – Keister Dee Dee Word of the Day – Dec. 14 – Keister By Staff mB - December 14, 2011 1031 Noun: Keister (KEE-stir) Definition: 1. A person’s buttocks. 2. A small suitcase or satchel. Sample sentence: He fell right on his keister in front of the whole crowd.