Proto-IE: *k'[ē]s-
Meaning: to show, to lead
Old Indian: śā́ste, śāsti `to correct, censure, control, teach', ptc. aor. śiṣánt- `teaching', ptc. śiṣṭá- `taught, controlled, shown'; śāstar- `chastiser, punisher'; śāstrá- n. `order, command; treatise'
Avestan: sāsti `heisst, lehrt'; sāstar- `Gebieter, Machthaber, Fürst'
Armenian: sast `Schelte, Vorwurf, Drohung, Strenge, Autorität', sastem `schelte, drohe, schärfe ein, gebiete', sastik `heftig'
Russ. meaning: указывать, руководить