Other forms: tracksuits
A tracksuit is the loose two-piece outfit worn for sport or for lounging. Zip-up top, matching bottoms.
It began as something athletes wore over their kit before a race, which is exactly what the name says, and became ordinary clothing in the 1980s. British English shortens it to trackie and calls the bottoms trackie bottoms. The word carries class associations in Britain that it does not carry elsewhere, which is worth knowing before using it about somebody.
1nountracksuitA matching loose top and trousers worn for sport or leisure.
“He came to the door in an old tracksuit.”
From track + suit.
Etymology from Wiktionary, CC BY-SA