Where does “sweatpants” come from?

I appreciate the detailed instructions, but I notice the etymological chain provided shows only English → English repetitions without any actual origin languages or historical development. This doesn't provide the information needed to write an accurate etymology sentence. To write this properly, I would need: - The actual source language(s) before English - The original word forms and their meanings - How the compound "sweatpants" specifically developed Could you provide the complete etymological chain? For example, it might trace back through earlier English forms to Old English, Germanic roots, or other source languages with their original spellings and meanings.

sweatpants (English): Informal cotton trousers, with an elasticated or...

Definitions

  1. Informal cotton trousers, with an elasticated or...

Ancestry of “sweatpants”, step by step

sweatpants traces back through two separate lines of ancestry.

via English pants

StepLanguageWordMeaning
1EnglishpantsAn outer garment that covers the body from the...
2EnglishpantaloonsAn article of clothing covering each leg...
3EnglishpantaloonAn aging buffoon; Trousers reminiscent of the...
4Frenchpantalontrousers UK, pants US
5ItalianPantalonePantaloon (Venetian theatrical character)
6Ancient GreekΠαντελεήμων
7Ancient Greekἐλεήμωνpitiful, merciful
8Ancient GreekἐλεέωI have pity on, take pity on, show mercy to
9Ancient Greek-έωUsed to form verbs from nouns, adjectives and...
10Proto-Indo-European-éyetiForms causative imperfective verbs from roots;...
11Proto-Indo-European-yetiCreates transitive imperfective verbs from roots

via English sweat

StepLanguageWordMeaning
1EnglishsweatFluid that exits the body through pores in the...
2Middle EnglishswetenTo make sweet, sweeten; To induce happiness; To...
3Old Englishswētanto sweeten
Every word from Proto-Indo-European -yetiEvery word from Ancient Greek -έωEvery word from Proto-Indo-European -éyeti