vas-

1.
variant of vaso- before a vowel:
vasectomy.
British Dictionary definitions for vas-

vas-

combining form
1.
a variant of vaso-

vaso-

combining form
1.
indicating a blood vessel: vasodilator
2.
indicating the vas deferens: vasectomy
Word Origin
from Latin vās vessel
vas- in Medicine

vas- pref.
Variant of vaso-.