Crossword Genius

Time for a celebration by a third at sea? (8)

Ross

I believe the answer is:

birthday

'time for a celebration' is the definition.

'by a third at sea?' is the wordplay.
'at sea?' indicates an anagram (I've seen 'at sea' mean this).
'by'+'a'+'third'='byathird'
'byathird' with letters rearranged gives 'BIRTHDAY'.

(Other definitions for birthday that I've seen before include "When presents are expected" , "Nothing to wear?" , "when one was delivered" , "When one receives cards" , "Invisible attire?" .)

I've seen this clue in The Telegraph.
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