Site of tower originally built north of Lincoln, Lincolnshire's capital (5)
I believe the answer is:
babel
'site of tower' is the definition.
'babel' can be an answer for 'tower' (I've seen this before). I'm not certain of the 'site of' bit.
'originally built north of lincoln lincolnshire's capital' is the wordplay.
'originally' indicates taking the first letters.
'north of' says to put letters next to each other (in a down clue, some letters go above others).
'lincoln' becomes 'abe' (Abraham Lincoln).
'capital' indicates taking the first letters.
The first letter of 'built' is 'b'.
The initial letter of 'lincolnshire' is 'l'.
'b'+'abe'+'l'='BABEL'
Can you help me to learn more?
(Other definitions for babel that I've seen before include "Biblical tower site" , "Confusion of sounds" , "Vocal confusion" , "Confusion of speech" , "Confusion of noise" .)