Eighteen holes are circular (5)

I believe the answer is:

round

I believe this is a double definition.

'eighteen holes' is the first definition.
(a round of golf includes eighteen holes)

'are circular' is the second definition.
(synonyms)

(Other definitions for round that I've seen before include "balls are like this" , "purchase of drinks" , "delivery trip?" , "with 6D [SPARE TYRE]" , "single slice of bread!" .)

I've seen this clue in The Irish Independent.

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