A "dog sweater" is a piece of clothing designed for dogs to help keep them warm just like how we wear sweaters to keep ourselves cozy when it's cold. Full definition
We carry large dog sweaters, costumes, dresses, and more to keep your larger dog looking their best. (poochieheaven.com)
Side note: If you just want to keep your dog warm indoors, then one of the products on our list of the best dog sweaters might be a better choice. (thedogclinic.com)
The best holiday dog sweaters should be fashionable and functional. (topdogtips.com)