BARN. Several Heb. and Gr. words are rendered “barn” in Eng. vss 1. גֹּ֫רֶן, H1755, meaning threshing floor (2 Kings 6:27; Job 39:12 ASV and RSV).

2. מְגוּרָה, H4476, in Joel 1:17 (KJV, ASV barns, RSV granaries).

3. אָסָם, H662, in Deuteronomy 28:8 (KJV storehouses, ASV, RSV barns).

4. ἀποθήκη, G630, tr. barn, meaning storehouse, granary (Matt 6:26; 13:30; Luke 12:18-24 KJV, ASV, RSV).

Grain was usually stored in a dry cistern in the ground, but sometimes in buildings.

International Standard Bible Encyclopedia (1915)

A place for the storing of grain, usually a dry cistern in the ground, covered over with a thick layer of earth. "Grain is not stored in the East until it is threshed and winnowed. The apotheke in Roman times was probably a building of some kind. But the immemorial usage of the East has been to conceal the grain, in carefully prepared pits or caves, which, being perfectly dry, will preserve it for years. It thus escaped, as far as possible, the attentions of the tax-gatherer as well as of the robber--not always easily distinguished in the East; compare Jer 41:8" (Temple Dictionary, 215).

Figurative of heaven (Mt 13:30).