One the bride might drag to the altar? (5)
I believe the answer is:
train
'one the bride might drag' is the definition.
I can't judge whether this definition defines the answer.
'the altar?' is the wordplay.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'altar?' becomes 'rain' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
't'+'rain'='TRAIN'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for train that I've seen before include "Aim < to prepare < railway carriages" , "Suite; give practice (in)" , "union's lengthy item" , "Linked carriages" , "Public transport on the railway" .)