Is there always room in this bar? (5)

I believe the answer is:

space

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'this bar?' is the definition.
(thesaurus)

I cannot understand how the remainder of the clue works.

(Other definitions for space that I've seen before include "Unfilled region" , "Gap between words" , "Gap; --- Oddity (Bowie)" , "Room; gap" , "Interstellar region" .)

I've seen this clue in the Evening Standard.

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