Decollation \De`col*la"tion\, n. [L. decollatio: cf. F. d['e]collation.] 1. The act of beheading or state of one beheaded; -- especially used of the execution of St. John the Baptist. [1913 Webster] 2. A painting representing the beheading of a saint or martyr, esp. of St. John the Baptist. [1913 Webster]