at sight adv. phr. 1. The first time the person or thing is seen; as soon as the person or thing is seen.
First graders learn to read many words on sight. Mary had seen many pictures of Grandfather, so she knew him on sight. Compare: AT ONCE
1.
2. On demand, on asking the first time.
The money order was payable at sight. [TahlilGaran] English Idioms Dictionary ▲