Infrastructure tools to support an effective radiation oncology learning health system

Underpants are underwear worn on the lower body generally extending no higher than the navel.^[1] In British English they are often called simply pants.^[2] If a given pair of underpants has a wider waistband, it might bear the brand name of the manufacturer on it.

Long underpants are the bottom half of a style of two-piece underwear called long underwear, long johns, or thermal underwear, that has long legs and long sleeves, and is normally worn during cold weather; also commonly worn by people under their clothes in cold countries. The male version of a long underwear bottom may or may not have a front fly.

Classic briefs have an elasticated waistband at or near the wearer's waist, and leg bands that end at or near the groin. Many male briefs feature a fly. They also come in ultra-absorbent varieties.

Bikini briefs are a variation on classic briefs that have less coverage; though typically full coverage of the derrière. Conventionally, the men’s version has no fly.

Thongs are like bikini briefs, except the backside is very narrow and goes between the buttocks.

Open drawers are undergarments where the backs and front of the legs are not joined together.

Diapers (North America) or nappies (Britain, Ireland, and Australia) are a type of underwear worn by young children and those suffering from incontinence. Unlike other briefs, diapers allow the wearer to urinate or defecate without soiling their surroundings. These can be either reusable or disposable.

Midway briefs are similar in style to boxer briefs, but are longer in the leg, at the longest being down to the knees.

Boxer shorts, boxers, or trunks (Britain),^[3] have an elasticated waistband that is at or near the wearer's waist, while the leg sections are fairly loose and extend to the mid-thigh. There is usually a fly, either with or without buttons.

Boxer briefs are similar in style to boxer shorts, but are form-fitting like classic briefs. Like men’s briefs, they often utilize a fly.

Sometimes boxer briefs are called trunks (Britain),^[4] see next section.

Trunk briefs, also known as simply trunks, are shorter than boxer briefs but still have leg sections, unlike briefs.^[5]

"Panties" is a general term for female underpants. There are a number of different styles including bikinis, boyshorts, briefs, cheekies, g-strings, hipsters, and thongs. The UK English equivalent is "knickers".

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  A male wearing long underwear
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  Male briefs
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  Male bikini briefs
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  Male thong
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  Midway briefs
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  Boxer shorts
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  Boxer briefs
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  Trunk briefs
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  Several styles of women's underpants (thong and G-string: back view)

• Leggings