IPA: /ˌoʊvərˈsi/
KK: /ˈoʊvərˌsi/
To watch over and direct the work or activities of someone or something; to supervise.
The manager will oversee the project to ensure it is completed on time.
Past: oversaw
Past Participle: overseen
Oversee is formed from "over-" (meaning above or beyond) and "see" (from Old English "seon", meaning to perceive or look at). The word means to look at or supervise something from above or a higher position.
Think of looking 'above' ('over-') to 'perceive' ('see') what is happening — that's why oversee means to supervise or manage.