A short time in submarines (3)
I believe the answer is:
mar
'a short time' is the definition.
The answer and definition can be both related to time as well as being singular nouns.
Maybe there's an association between them I don't understand?
'in submarines' is the wordplay.
'in' says the answer is hidden in the clue.
'MAR' is hidden in the letters of 'submarines'.
Can you help me to learn more?
(Other definitions for mar that I've seen before include "Ruin" , "Make imperfect" , "Detract from" , "Blemish" , "Ram into and spoil" .)