Is SIZES a Wordle Word?

Yes. SIZES 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 SIZES mean?

(obsolete outside dialectal) An assize.
A regulation determining the amount of money paid in fees, taxes etc.
A fixed standard for the magnitude, quality, quantity etc. of goods, especially food and drink.

6 more noun definitions

The dimensions or magnitude of a thing; how big something is.“The size of the building seemed to have increased since I was last there.”
A regulation, piece of ordinance.
A specific set of dimensions for a manufactured article, especially clothing.“I don't think we have the red one in your size.”
A number of edges in a graph.
Degree of rank, ability, character, etc.
An instrument consisting of a number of perforated gauges fastened together at one end by a rivet, used for measuring the size of pearls.

3 more verb definitions

To take a greater size; to increase in size.
(Cambridge University) To order food or drink from the buttery; hence, to enter a score, as upon the buttery book.
To swell; to increase the bulk of.

A thin, weak glue used as primer for paper or canvas intended to be painted upon.
Wallpaper paste.
The thickened crust on coagulated blood.

1 more noun definition

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

Starter word rating: WeakIn the top 76% of all valid Wordle words for testing common letters.
Vowels: I, E
Unique letters: 4 of 5Repeats S
Common letters: I, E
Rare letters: Z

Hard-mode trap: 11 valid words fit the pattern SI_ES. 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.