An Etymological Dictionary of Astronomy and Astrophysics

To take or fill up (space, time); to take possession and control of a place.

Etymology (EN): From O.Fr. occuper, from L. occupare “take over, seize, possess, occupy,” from ob “over” + intensive form of capere “to grasp, seize, take;” PIE base *kap- “to grasp” (cf. Skt. kapati “two handfuls;” Gk. kaptein “to swallow,” O.Ir. cacht “servant-girl,” literally “captive;” Goth. haban “have, hold;”
O.E. habban “to have, hold,” probably Mod.Pers. qâp-, qâpidan “to seize;”
Av. haf-, hap- “to keep, observe.”

Etymology (PE): Hagidan, from dialectal Pers.: Šahmirzâdi hâgetan, Saraxsi hagiton, Tabari hâytan, haytan,
Semnâni hâtan, Gilaki hâgitan, Lâsgardi agiton, degiton “to occupy;”
maybe related to Av. haz- “to occupy;” Skt. sah- “to overcome, be victorious, prevail,” saha- “victory,” sahate “overcomes, masters;” Gk. ekhein “to have, hold;” PIE base *segh- “to have, to hold.”