Combinations (pettycoats, clothes etc) are known as what in the United States?

I'd better point out that combinations (usually said 'coms') in the UK can be combination of long-johns and vest (that's singlet, to you lot over there). In case long-johns have a different name too, they're longlegged undergarments worn by men in winter. Great for cycling in the mid-winter. Both long-johns and (especially) combinations are getting rarer, as only outdoor people really need them now. Almost all indoor work is warm now.

For women, "combinations" were once a garment combining a chemise and drawers in one. They emerged onto the underwear scene in the late 19th century and became more popular in the early 20th, when there was a trend towards less -- and less bulky -- underclothing. The closest equivalent today would be a teddy.

I don't imagine that many people today wear the old one-piece "union suit." Instead, as Baloo indicates, they wear a two-piece outfit under their clothing, usually only for cold-weather activities. The term I now hear most often is "thermal underwear," not "long johns," though I'm sure some people still use the latter.

Scroll down for ladies' "combinations":


http://www.tudorlinks.com/treasury/articles/viewvictunder1.html

Americans call singlets "undershirts." The younger people call them "wifebeaters," for whatever reason I've been unable to discern, but I do think K-Mart or WalMart or some such got in trouble for using the term in an ad.

Everyone I knows says "long johns," but the packages sometimes say that and sometimes say "thermal underwear."

If a union suit is a teddy, we really have come a long way, baby! Guess we have, though the two garments have entirely different purposes.
https://en.wikipedia.org/wiki/Union_suit

No, qp, my first paragraph concerned ladies' underwear only. The second was about other items, including the classic union suit and today's thermal underwear. I did not identify the "union suit" with the "teddy." I was simply trying to point out that the term "combinations" once had a meaning specifically associated with a one-piece feminine undergarment.

The British authors Jon and Rumer Godden, describing their childhood in India, complained that the early 20th-century Raj English, insisting on changing three times a day, put their young daughters into heavily-starched "combinations" beneath their fancy afternoon dresses. As the Goddens pointed out, these garments often resulted in "crises at certain important moments."

Yes, now I see you did focus on ladies in your first paragraph. Even though ladies, not men, originally wore union suits, you weren't talking about that. They are still readily available, amusingly enough.
http://www.campmor.com/webapp/wcs/stores/servlet/ProductDisplay?productId=17988&memberId=12500226

Orwell taught me "singlets" and "spanners," but it took Fun Trivia to teach me "combinations." Thanks, all.

(Yes, I realize "spanners" aren't underwear.)

Actually, Baloo wasn't referring to two piece garments, but to a single thing referred to as 'coms' - vest and pants all in one. A bit like a boiler suit, only closer fitting.... And no pockets.