Light drink around start of meal (4)
I believe the answer is:
lamp
'light' is the definition.
(lamp is a kind of light)
'drink around start of meal' is the wordplay.
'drink' becomes 'lap' (to lap is to drink up).
'around' is an insertion indicator.
'start of' indicates taking the first letters.
The initial letter of 'meal' is 'm'.
'lap' enclosing 'm' is 'LAMP'.
(Other definitions for lamp that I've seen before include "This could be standard" , "punch" , "Device for giving light on palm" , "Artificial source of illumination" , "Aladdin's - -" .)