Vessel dropping off a US magazine in midday break (9)
I believe the answer is:
lunchtime
'midday break' is the definition.
(I've seen this before)
'vessel dropping off a us magazine' is the wordplay.
'vessel' becomes 'launch' (launch is a type of motorboat).
'dropping off' is a deletion indicator.
'us magazine' becomes 'time' (US weekly magazine).
'launch' with 'a' taken out is 'lunch'.
'lunch'+'time'='LUNCHTIME'
'in' is the link.
(Other definitions for lunchtime that I've seen before include "Maybe one" , "When to take a short break" , "One possibly" , "When midday meal is eaten" , "Midday period for eating" .)