IPA: /rɪˈstɑːtəbl/
KK: /riˈstɑrtəbl/
Able to be started again after stopping or being interrupted.
The software is designed to be restartable in case of a failure.
Restartable → It is formed from "re-" (meaning again) and "start" (from Old English "styrtan", meaning to leap up or begin) and "-able" (meaning capable of). The word "restartable" means capable of starting again.
Think of 'again' ('re-') and 'beginning' ('start') — that's why restartable means something that can begin again.