shaped like an upsilon
• (a.) Resembling the / in appearance; -- said of the germinal spot in the ripe egg at one of the stages of fecundation.
Yp·sil'i·form adjective [ Greek ... ... the name of the letter ... + -form .] (Biol.) Resembling the ... in appearance; -- said of the germinal spot in the ripe egg at one of the stages of fecundation. 
Type: Term Pronunciation: ip-sil′i-fōrm Synonyms: hypsiloid