Is EIDER a Wordle Word?

Yes. EIDER is a valid Wordle word.

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

What does EIDER mean?

/ˈaɪdə/

Any of the species of the genera Polysticta or Somateria, in the seaduck subfamily Merginae, which line their nests with fine down (taken from their own bodies).

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

Starter word rating: AverageIn the top 39% of all valid Wordle words for testing common letters.
Vowels: E, I
Unique letters: 4 of 5Repeats E
Common letters: E, I, R

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