ypsiliform

from The Century Dictionary.

• Shaped like the Greek capital letter Υ; Y-shaped. The figure is also called arietiform, the symbol of the zodiacal sign Aries being the same.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Biol.) Resembling the � in appearance; -- said of the germinal spot in the ripe egg at one of the stages of fecundation.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective in the shape of an ypsilon