Undershirt
An undershirt is an article of underwear worn underneath a dress shirt intended to protect it from body sweat and odors. It can have short sleeves (T-shirt) or be sleeveless (A-shirt). The term most commonly refers to upper-body wear worn by males.
An undershirt may be worn to protect the body from stiff or otherwise uncomfortable fabric. It also makes dress shirts less transparent, can be worn during winter months as an extra layer of warmth, and reduces wear on the upper layers of clothing.
Undershirt (noun)
An undergarment worn beneath a shirt, often collarless and sleeveless.
Onesie (noun)
A one-piece garment for an infant or small child, generally worn over a diaper.
Onesie (noun)
One-piece adult loungewear jumpsuit.
Onesie (noun)
One-piece fashionable streetwear worn mostly by teenagers.
Onesie (noun)
a loose-fitting one-piece leisure garment covering the torso and legs
“I’d had a bath and was in my onesie ready to settle down for yet another reality TV marathon”
Onesie (noun)
a one-piece close-fitting lightweight garment worn by a young child, usually having sleeves but leaving the legs uncovered and fastening with press studs at the crotch.