Jeans (8)
(Other definitions for trousers that I've seen before include "Corduroys or chinos" , "Longs" , "Pants" , "pockets" , "Nether garments now worn by either sex" .)
(Other definitions for mom that I've seen before include "A familiar American mother" , "US mother, in short" , "'US mother, informally (3)'" .)
'jeans' is the definition.
('denim' can be a synonym of 'jean')
This is the entire clue.
(Other definitions for denims that I've seen before include "hard-wearing trousers" , "Hard-wearing clothes for work or play" , "Jeans" , "Clothes made of strong twilled cotton fabric" .)