Comments: Obl. base *psṭuw-nV-, cf. Chech. stūna-, Ing. suwno, Bacb. pstujnĩ; cf. also Bacb. psṭujnŏ "woman". An interesting compound is Chech. stun-da "father-in-law" ("wife's father") = Ing. ust-da, where Ing. has a prothetic vowel and preserves the -st- combination. Cf. also Cheb. stu, Shar., Khild. su.