Posted on the way to the theatre (4)
I believe the answer is:
sent
'posted' is the definition.
('send' can be a synonym of 'post')
'on the way to the theatre' is the wordplay.
'on' says to put letters next to each other.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'way' becomes 's' (Compass direction - South).
'to the theatre' becomes 'en' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
's'+'en'='sen'
't' put after 'sen' is 'SENT'.
Can you help me to learn more?
(Other definitions for sent that I've seen before include "Thrilled" , "Despatched" , "old money in Tallinn" , "Posted" , "Remitted" .)