First nine letters of alphabet written up - culminating in this? (4)
I believe the answer is:
iota
'first nine' is the definition.
The definition and answer can be both quantities as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'letters of alphabet written up culminating in this?' is the wordplay.
I cannot quite see how this works, but
'of' could be 'o' and 'o' is found in the answer.
The remaining letters 'ita' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
(Other definitions for iota that I've seen before include "Scintilla" , "Tiniest scrap" , "Tiny piece" , "'Very small amount, jot (4)'" , "Trace" .)