check on someone or something
to look into the legitimacy or condition of someone or something. Sarah will check on the matter and report to us. I will check on Jeff while he's not feeling well.
Also, check up on ; check over. Investigate, scrutinize, or inspect, as in I'll check on the brakes and make sure they're all right, or We need to check up on his work from time to time, or Let's check over the books together. [Late 1800s] Also see check out, def. 6.
check onor check up on
To inspect someone or something that one is supervising or watching over: I checked on the meatloaf in the oven to see if it was ready to eat. Go upstairs to check up on the children and make sure they're all asleep.