Strong's #4763: mra'ashah (pronounced mer-ah-ash-aw')
 formed like 4761; properly, a headpiece, i.e. (plural for adverbial) at (or as) the head-rest (or pillow):--bolster, head, pillow. Compare 4772.
Brown-Driver-Briggs Hebrew Lexicon:
 ׁ 
  mera'ăshâh 
 
 1) place at the head, dominion, head place (noun feminine)
 2) at head place (adverb)
 
  Part of Speech: see above in Definition
Relation: formed like H4761
Usage:
This word is used 9 times:
Genesis 28:11: "and he took of the stones of that place, and put  them for his pillows, and lay down in that"
Genesis 28:18: "the stone that he had put  for his pillows, and set it up for a pillar, and poured"
1 Samuel 19:13: "and put a pillow of goats'  hair for his bolster, and covered it with a cloth."
1 Samuel 19:16: "the bed, with a pillow of goats'  hair for his bolster."
1 Samuel 26:7: "and his spear stuck in the ground  at his bolster: but Abner and the people lay round about"
1 Samuel 26:11: "take thou now the spear that  is at his bolster, and the cruse of water,"
1 Samuel 26:12: "and the cruse of water from Saul's  bolster; and they got them away, and no man saw it, nor"
1 Samuel 26:16: "spear is, and the cruse of water that  was at his bolster."
1 Kings 19:6: "baked on the coals, and a cruse of water  at his head. And he did eat and drink, and laid him down again."