Is BETAS a Wordle Word?

Yes. BETAS 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 BETAS mean?

The second letter of the Greek alphabet (Β, β), preceded by alpha (Α, α) and followed by gamma, (Γ, γ). In modern Greek it represents the voiced labiodental fricative sound of v found in the English words have and vase.
Used in marking scheme: α, β, γ or α+, α, α-, β etc.
Average sensitivity of a security's price to overall securities market prices.

5 more noun definitions

The phase of development after alpha testing and before launch, in which software, while not complete, has been released to potential users for testing.“The company is offering a public beta program to test the software.”
Software in such a phase; a preliminary version.
Information about a route which may aid someone in climbing it.
A beta particle or beta ray.
In omegaverse fiction, a person of a (usually secondary) gender/sex that mirrors the biology of a normal human, being free from the biological drives of alphas and omegas but generally capable of bonding and mating with either.

To preliminarily release computer software for initial testing prior to final release.
To beta-read a text.

(manosphere, pickup community) A man who is less competent or desirable than an alpha male.

Any fish of the genus Betta, especially Betta splendens (the Siamese fighting fish).

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

Starter word rating: GoodIn the top 7% of all valid Wordle words for testing common letters.
Vowels: E, A
Unique letters: 5 of 5
Common letters: E, T, A

Hard-mode trap: 8 valid words fit the pattern _ETAS. 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.