Reference: Bolster
Easton
The Hebrew word kebir, rendered "pillow" in 1Sa 19:13,16, but in Revised Version marg. "quilt" or "network," probably means some counterpane or veil intended to protect the head of the sleeper. A different Hebrew word (meraashoth') is used for "bolster" (1Sa 26:7,11,16). It is rightly rendered in Revised Version "at his head." In Ge 28:11,18 the Authorized Version renders it "for his pillows," and the Revised Version "under his head." In Eze 13:18,20 another Hebrew word (kesathoth) is used, properly denoting "cushions" or "pillows," as so rendered both in the Authorized and the Revised Version.
See Verses Found in Dictionary
Fausets
The pillow of goat's hair which Michal put for a bolster (1Sa 19:13) was probably a curtain to protect the sleeper from mosquitoes, or a counterpane, with which sleepers in the East protect the head and face. Kebir means something woven, from kaabar "to weave." The indefinite article implies it was one of the articles of regular use, as a counterpane or veil woven of goat's hair to cover the head and face while sleeping.