Is KOLOS a Wordle Word?

Yes. KOLOS is a valid Wordle word.

It is not on the Wordle answer list, so it is unlikely to be a daily answer.

Plurals ending in S are almost never chosen as Wordle answers.

What does KOLOS mean?

A national folk dance common in regions pertaining to South Slavic people, performed in a circle.“1942: As we came to this promenade [...] we heard the throbbing of a drum that announces a kolo, a communal dance. — Rebecca West, Black Lamb and Grey Falcon (Canongate 2006, p. 660)”

Definition from Wiktionary, available under the CC BY-SA license.

Starter word rating: WeakIn the top 86% of all valid Wordle words for testing common letters.
Vowels: O
Unique letters: 4 of 5Repeats O
Common letters: O, L

Hard-mode trap: 10 valid words fit the pattern _OLOS. If you reach it, you may need several guesses to find the last letter.

Letter ratings use how often each letter appears in Wordle answers.

Tap its tiles to the colours Wordle showed, and the Wordle Solver lists every word that still fits, with the best next guess.