Briefly carry toddler (3)
I believe the answer is:
tot
'toddler' is the definition.
('tot' can be a synonym of 'toddler')
'briefly carry' is the wordplay.
'briefly' means to remove the last letter.
'carry' becomes 'tote' (toting is a kind of carrying).
'tote' with its last letter taken away is 'TOT'.
(Other definitions for tot that I've seen before include "Add up like infant" , "Small baby" , "Aggregate for infant" , "Child's" , "Small drink; accumulate" .)