sweater

word building
Other words for sweater are jersey, jumper and pullover. Sweaters are often made of wool. A cardigan is a sweater that fastens at the front like a jacket.

Longman Dictionary of Contemporary English

sweater

sweat‧er /ˈswetə $ -ər/ BrE AmE noun [countable]
[Date: 1800-1900; Origin: sweat; because it was originally worn when doing exercise, to make you sweat]

a piece of warm wool or cotton clothing with long sleeves, which covers the top half of your body SYN jumper British English

Oxford Advanced Learner's Dictionary

sweater

sweat·er [sweater sweaters] [ˈswetə(r)] [ˈswetər] noun

a knitted piece of clothing made of wool or cotton for the upper part of the body, with long sleeves. In British English the word is used to describe a piece of clothing with no buttons. In American English a sweater can have buttons and be like a jacket.

Cambridge Advanced Learner's Dictionary

Cambridge Advanced Learner's Dictionary - 4th Edition

sweater / ˈswet.ə r / / ˈswet̬.ɚ / noun [ C ] ( UK also jumper )

A2 a piece of clothing with long sleeves that is usually made from wool, worn on the upper part of the body:

Put a sweater on if you're cold.

a V-necked sweater

→ Compare cardigan

Collins COBUILD Advanced Learner’s English Dictionary

sweater

/swetə(r)/
(sweaters)

A sweater is a warm knitted piece of clothing which covers the upper part of your body and your arms.

= jumper, pullover

N-COUNT

Merriam-Webster's Advanced Learner's Dictionary

Merriam-Webster's Advanced Learner's Dictionary:

sweater

sweat·er /ˈswɛtɚ/ noun, pl -ers [count] : a warm usually knitted piece of clothing for the upper part of your body: such as
a : one that is put on by pulling it over your head : pullover
- called also (Brit) jumper,
- see color picture
b US : one that opens like a jacket and that is fastened in the front with buttons or a zipper - called also cardigan,