C2 [ T ] to look at something carefully, with the eyes or with a machine, in order to get information:
She anxiously scanned the faces of the men leaving the train.
Doug scanned the horizon for any sign of the boat.
C1 [ I + adv/prep, T ] to look through a text quickly in order to find a piece of information that you want or to get a general idea of what the text contains:
I scanned through the booklet but couldn't find the address.
Scan the newspaper article quickly and make a note of the main points.