From an unused root meaning to store; treasure; by implication, a coffer -- chest, treasury.
H1595. genez
[גְּנָזִים] noun [masculine] plural
1 chests (?);
2 treasury — only plural constructגִּנְזֵי; — 1 perhaps chests of variegated cloth ׳ג בְּרֹמִים Ezekiel 27:24 so Thes AV RV; Sm Co and others cloths, carpets, Ew Taschen. 2 treasury (Late Hebrew גֶּנֶז, Aramaic גְּנִיז גִּנְזָא,, Biblical Aramaic construct plural גִּנְזֵי; Persian loan-word from treasure? compare Vullersii.1032 LagGes.Abh.27); הַמֶּלֶךְ גִּנְזֵי Esther 3:9; 4:7.
[גְּנַז] noun masculineEzra 6:1 treasure (ᵑ7; see Biblical Hebrew [ גְּנָזִים], below גנז); — plural emphatic גִּנְזִיָּא treasures 6:1, ׳ג בֵּית מַלְכָּא דִּי 5:17, construct מִלְכָּא גִּנְזֵי בֵּית 7:20.