A building housing many wards? (9)

I believe the answer is:

orphanage

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'a building' is the definition.
(I've seen this before)

I don't understand the remainder of the clue.

(Other definitions for orphanage that I've seen before include "left children here?" , "home for little Annie" , "with deprived children" , "building" , "Children's home" .)

I've seen this clue in The Sunday Times.

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