One in time to join up? (6)
I believe the answer is:
stitch
'one' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'time to join up?' is the wordplay.
'time' becomes 't' (abbreviation).
'to join' indicates putting letters inside (inserted letters join the word).
'up?' becomes 'sitch' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
't' going inside 'sitch' is 'STITCH'.
'in' is the link.
Can you help me to learn more?
(Other definitions for stitch that I've seen before include "One in time saves nine" , "herringbone?" , "Link, loop or knot made in knitting or sewing" , "Something surgeon provides" , "A sewer may produce such" .)