Pajamas is the usual American spelling of the loose top and trousers people wear in bed. British English writes pyjamas. Same clothes, same word — only the letters change.

Pajamas pajamas is是 the usual American spelling一般美式的拼法 of the loose top and trousers people wear in bed指人們睡覺時穿的寬鬆上衣和褲子。British English英式英語 writes寫成 pyjamas pyjamas。Same clothes同樣的衣服, same word同樣的字 — only the letters change只是拼法不一樣。

Americans also use pajama in front of another noun: pajama bottoms, a pajama party. For the whole set, people still say a pair of pajamas, the way they say a pair of trousers. It is home language, not formal.

Americans美國人 also use把pajama放在另一個名詞前面用 pajama in front of another noun: pajama bottoms睡褲, a pajama party睡衣派對。For the whole set指整套衣服時, people大家 still say還是會說 a pair of pajamas一套pajamas, the way they say就像他們說 a pair of trousers一條褲子一樣。It它 is是 home language居家用語, not formal不是正式用字。

The word came into English from Hindustani (Hindi pājāmā / Urdu pājāma), and before that from Classical Persian pājāma, “trousers”: pā “leg” + jāma “garment”. So it first meant loose trousers; English later used it for night clothes as a set.

The word這個字 came into English進入英文, from Hindustani是從印度斯坦語來的 (Hindi pājāmā / Urdu pājāma)（印地語pājāmā／烏爾都語pājāma）, and而 before that再更早, from Classical Persian pājāma是從古典波斯語的pājāma而來, “trousers”意思是「褲子」: pā “leg”pā是「腿」 + jāma “garment”加上jāma「衣服」。So所以, it它 first meant最初的意思是 loose trousers寬鬆的褲子; English later used it英文後來把它用來指 for night clothes as a set一整套的睡衣。

Though actually, related words in some South Asian languages still mean daytime trousers, not sleepwear. English moved the meaning.

Though actually不過, related words in some South Asian languages一些南亞語言裡的相關字 still mean現在還是指 daytime trousers白天穿的褲子, not sleepwear而不是睡衣。English英文 moved the meaning把意思給移動了。