is based on Hbr. yätär, Syr. yatrā, Arb. watar-, Gez. watr, Amh. wätär (some of them with non-anatomic meanings like ‘rope’, ‘cord’, ‘bowstring’)
PWS
*yapan- - young bull
(SED II No. 250)
Note the prefixal elements tV-,mV-,wV- of unclear origin in all Eth. forms.
Arb.fanāt- probably represents an original biconsonantal prototype.