Glossary

Underwear is defined as clothing or an article of clothing worn next to the skin and under other clothing. Boxer shorts, briefs, thongs, bikini, boxer briefs, panties etc.

Undies is another word for underwear. More of a slang word used in the English language. It is also sometimes called underclothes.

Underclothing is synonymous to underwear.

Underdrawers are articles of underwear for the lower body

Undergarment is defined as cloth to be worn under another

Undershirt refers to a collarless undergarment with or without sleeves

Underskirt pertains to a skirt worn under an outer skirt, as in a petticoat

See also:
"Underwear" is in the NAICS Code "315192"
  (Underwear and Nightwear Knitting MillsT-shirts, underwear, made in apparel knitting mills)

Underwear clothing or an article of clothing worn next to the skin and under other clothing. Boxer shorts, briefs, thongs, bikini, boxer briefs, panties etc.

-see also:
"Underwear" is in the NAICS Code "315192"
  (Underwear and Nightwear Knitting MillsRobes, lounging, made in apparel knitting mills)