About to enter the time (5)
I believe the answer is:
three
'time' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'about to enter the' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'to enter' indicates putting letters inside.
're' going within 'the' is 'THREE'.
Can you help me to learn more?
(Other definitions for three that I've seen before include "Sixth root of seven hundred and twenty nine" , "Number that's a crowd" , "One, one, one" , "So many 12s today" , "Trinity, triad" .)