‖ pileolusBot.|pɪˈliːələs| [L. pīleolus (better pill-), dim. of pileus.] A little pileus; as the small cap-like receptacle of certain fungi. 1858in Mayne Expos.Lex.1866Treas.Bot., Pileolus, a little cap or cap-like body..; the receptacle of certain fungals.