TgJ Jud10:8 :וֻדחַקֻו וְשַעְבִידֻו יָת בְנֵי יִשׂרָאֵל בְשַתָא הַהִיא תַמנַא עַסרֵי שְנִין‏ : that year they oppressed and enslaved the Israelites for 18 years
See the entire entry for šˁbd vb. to enslave