What does “by sight” mean in this context? [closed]

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What does “by sight” mean in this context? [closed]
They know him well by sight.
Could you explain that what does "by sight" here ?
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1 Answer
1
By sight:
by appearance; by recognizing but not through being acquainted.
(Collins Dictionary)
So if you know someon by sight, it means you can recognize them because you often see them, for instance, but not because you know them in person.
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Did you check any dictionaries @Hasan?
– AmirhoseinRiazi
Sep 3 at 16:31