Today’s word, oology, refers to the study of eggs, especially bird’s eggs. It also covers the collecting of bird’s eggs and the study of their breeding habits, and their nests, a practice sometimes known as caliology.

Oology is sometimes written oölogy, comes from the Greek ōion, egg, plus ology, a back formation from words like biology.

I came across this word in Jasper Fforde’s wonderfully silly book The Big Over Easy, which centres around the mysterious death of Humpty Dumpty - did he fall or was he pushed?. Oologists are consulted during the investigation.