a large shallow vat; a cistern, tub, or trough, used by brewers, distillers, dyers, picklers, gluemakers, and others, for mixing or cooling wort, holding water, hot glue, etc.-a ferryboat.  see bac, 1.-in human beings, the hinder part of the body, extending from the neck to the end of the spine; in other animals, that part of the body which corresponds most nearly to such part of a human being; as, the back of a horse, fish, or lobster.-an extended upper part, as of a mountain or ridge.-the outward or upper part of a thing, as opposed to the inner or lower part; as, the back of the hand, the back of the foot, the back of a hand rail.-the part opposed to the front; the hinder or rear part of a thing; as, the back of a book; the back of an army; the back of a chimney.-the part opposite to, or most remote from, that which fronts the speaker or actor; or the part out of sight, or not generally seen; as, the back of an island, of a hill, or of a village.-the part of a cutting tool on the opposite side from its edge; as, the back of a knife, or of a saw.-a support or resource in reserve.-the keel and keelson of a ship.-the upper part of a lode, or the roof of a horizontal underground passage.-a garment for the back; hence, clothing.-being at the back or in the rear; distant; remote; as, the back door; back settlements.-being in arrear; overdue; as, back rent.-moving or operating backward; as, back action.-to get upon the back of; to mount.-to place or seat upon the back.-to drive or force backward; to cause to retreat or recede; as, to back oxen.-to make a back for; to furnish with a back; as, to back books.-to adjoin behind; to be at the back of.-to write upon the back of; as, to back a letter; to indorse; as, to back a note or legal document.-to support; to maintain; to second or strengthen by aid or influence; as, to back a friend.-to bet on the success of; -- as, to back a race horse.-to move or go backward; as, the horse refuses to back.-to change from one quarter to another by a course opposite to that of the sun; -- used of the wind.-to stand still behind another dog which has pointed; -- said of a dog.-in, to, or toward, the rear; as, to stand back; to step back.-to the place from which one came; to the place or person from which something is taken or derived; as, to go back for something left behind; to go back to one's native place; to put a book back after reading it.-to a former state, condition, or station; as, to go back to private life; to go back to barbarism.-(of time) in times past; ago.-away from contact; by reverse movement.-in concealment or reserve; in one's own possession; as, to keep back the truth; to keep back part of the money due to another.-in a state of restraint or hindrance.-in return, repayment, or requital.-in withdrawal from a statement, promise, or undertaking; as, he took back0 the offensive words.-in arrear; as, to be back in one's rent.