[ ˌvɛsɪkə'pɪskɪs , 'vi:- ]
■ noun ( plural vesicae piscis 'vɛsɪki: , 'vi:- ) a pointed oval shape used as an architectural feature and as an aureole enclosing figures such as Christ or the Virgin Mary in medieval art.
Origin
L., lit. 'fish's bladder'.