For holding oil or perfumery (Mark 14:3). It was of the form of a flask or bottle. The Hebrew word (pak) used for it is more appropriately rendered “vial” in 1 Sam. 10:1, and should also be so rendered in 2 Kings 9:1, where alone else it occurs.
Easton’s Bible Dictionary
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Easton’s Bible Dictionary (1897), public domain. Text via Theographic Bible Metadata, CC BY-SA 4.0.