זיז Ziz
Every verse in which this word stands as the creature — 2 places, in canonical order, first appearance to last. The word's lexicon entry carries more than the creature, so these are the creature's own verses — the row's note says what the other places are.
'The ziz of the fields is with Me' — Tehillim 50:11, and again 80:14, and only there as a creature. The plain sense is whatever moves in the field; the Midrash knows the Ziz as the great bird, beside Leviathan of the sea and Behemot of the land. In Yeshayahu 66:11 the same letters mean abundance, and that place is not counted here.
יָדַעְתִּי כָּל־עוֹף הָרִים וְזִיז שָׂדַי עִמָּדִֽי
I know all the fowls of the mountains; and the wild beasts of the field are Mine.
יְכַרְסְמֶנָּֽה חֲזִיר מִיָּעַר וְזִיז שָׂדַי יִרְעֶֽנָּה
The boar out of the wood doth ravage it, That which moveth in the field feedeth on it.
Quick answers
What is the Hebrew word for ziz?
Ziz in Hebrew is זיז, with a gematria of 24 in the standard method.
How many times is the ziz mentioned in the Tanakh?
The word stands 2 times as the creature, first at Psalms 50:11.
A spelling is not a word. The corpus never writes זיז bare — every one of its places carries a particle or a suffix on the front or the back — so the spelling above is the word's own headword, and the verses listed here are the only door to it.