'Childermas day' definitions:

Definition of 'Childermas day'

From: GCIDE

Childermas day \Chil"dermas day`\ [AS. cildam[ae]sse-d[ae]g; cild child +d[ae]g day.] (Eccl.) A day (December 28) observed by mass or festival in commemoration of the children slain by Herod at Bethlehem; -- called also Holy Innocent's Day. [1913 Webster]