The Collaborative International Dictionary
Cornercap
Cornercap \Cor"ner*cap`\ (-k?p`), n. The chief ornament. [Obs.]
Thou makest the triumviry the cornercap of society.
--Shak.
Wiktionary
cornercap
n. 1 (context obsolete English) A priest's or academic's hat. 2 (context obsolete English) The chief ornament.