Hop back,
Jack back, the cistern which receives the infusion of malt and hops from the copper. --
Wash back, a vat in which distillers ferment the wort to form wash. --
Water back, a cistern to hold a supply of water; esp. a small cistern at the back of a stove, or a group of pipes set in the fire box of a stove or furnace, through which water circulates and is heated. [ 1913 Webster ]

2. A ferryboat. See Bac, 1. [ 1913 Webster ]

2. An extended upper part, as of a mountain or ridge. [ 1913 Webster ]

[ The mountains ] their broad bare backs upheave
Into the clouds. Milton. [ 1913 Webster ]

3. 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. [ 1913 Webster ]

Methought Love pitying me, when he saw this,
Gave me your hands, the backs and palms to kiss. Donne. [ 1913 Webster ]

4. 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. [ 1913 Webster ]

5. 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. [ 1913 Webster ]

6. The part of a cutting tool on the opposite side from its edge; as, the back of a knife, or of a saw. [ 1913 Webster ]

7. A support or resource in reserve. [ 1913 Webster ]

This project
Should have a back or second, that might hold,
If this should blast in proof. Shak. [ 1913 Webster ]

8. (Naut.) The keel and keelson of a ship. [ 1913 Webster ]

9. (Mining) The upper part of a lode, or the roof of a horizontal underground passage. [ 1913 Webster ]

10. A garment for the back; hence, clothing. [ Obs. ] [ 1913 Webster ]

A bak to walken inne by daylight. Chaucer. [ 1913 Webster ]

Behind one's back, when one is absent; without one's knowledge; as, to ridicule a person behind his back. --
Full back,
Half back,
Quarter back (Football), players stationed behind those in the front line. --
To be on one's back or
To lie on one's back, to be helpless. --
To put one's back up or
to get one's back up, to assume an attitude of obstinate resistance (from the action of a cat when attacked). [ Colloq. ] --
To see the back of, to get rid of. --
To turn the back, to go away; to flee. --
To turn the back on one, to forsake or neglect him. [ 1913 Webster ]

2. Being in arrear; overdue; as, back rent. [ 1913 Webster ]

3. Moving or operating backward; as, back action. [ 1913 Webster ]

Back blocks, Australian pastoral country which is remote from the seacoast or from a river. [ Webster 1913 Suppl. ] --
Back charges, charges brought forward after an account has been made up. --
Back filling (Arch.), the mass of materials used in filling up the space between two walls, or between the inner and outer faces of a wall, or upon the haunches of an arch or vault. --
Back pressure. (Steam Engine) See under Pressure. --
Back rest, a guide attached to the slide rest of a lathe, and placed in contact with the work, to steady it in turning. --
Back slang, a kind of slang in which every word is written or pronounced backwards; as, nam for man. --
Back stairs, stairs in the back part of a house; private stairs. Also used adjectively. See Back stairs, Backstairs, and Backstair, in the Vocabulary. --
Back step (Mil.), the retrograde movement of a man or body of men, without changing front. --
Back stream, a current running against the main current of a stream; an eddy. --
To take the back track, to retrace one's steps; to retreat. [ Colloq. ] [ 1913 Webster ]

1. To get upon the back of; to mount. [ 1913 Webster ]

I will back him [ a horse ] straight. Shak. [ 1913 Webster ]

2. To place or seat upon the back. [ R. ] [ 1913 Webster ]

Great Jupiter, upon his eagle backed,
Appeared to me. Shak. [ 1913 Webster ]

3. To drive or force backward; to cause to retreat or recede; as, to back oxen. [ 1913 Webster ]

4. To make a back for; to furnish with a back; as, to back books. [ 1913 Webster ]

5. To adjoin behind; to be at the back of. [ 1913 Webster ]

A garden . . . with a vineyard backed. Shak. [ 1913 Webster ]

The chalk cliffs which back the beach. Huxley. [ 1913 Webster ]

6. To write upon the back of; as, to back a letter; to indorse; as, to back a note or legal document. [ 1913 Webster ]

7. To support; to maintain; to second or strengthen by aid or influence; as, to back a friend. “The Parliament would be backed by the people.” Macaulay. [ 1913 Webster ]

Have still found it necessary to back and fortify their laws with rewards and punishments. South. [ 1913 Webster ]

The mate backed the captain manfully. Blackw. Mag. [ 1913 Webster ]

8. To bet on the success of; -- as, to back a race horse. [ 1913 Webster ]

To back an anchor (Naut.), to lay down a small anchor ahead of a large one, the cable of the small one being fastened to the crown of the large one. --
To back the field, in horse racing, to bet against a particular horse or horses, that some one of all the other horses, collectively designated “the field”, will win. --
To back the oars, to row backward with the oars. --
To back a rope, to put on a preventer. --
To back the sails, to arrange them so as to cause the ship to move astern. --
To back up, to support; to sustain; as, to back up one's friends. --
To back a warrant (Law), is for a justice of the peace, in the county where the warrant is to be executed, to sign or indorse a warrant, issued in another county, to apprehend an offender. --
To back water (Naut.), to reverse the action of the oars, paddles, or propeller, so as to force the boat or ship backward. [ 1913 Webster ]

2. (Naut.) To change from one quarter to another by a course opposite to that of the sun; -- used of the wind. [ 1913 Webster ]

3. (Sporting) To stand still behind another dog which has pointed; -- said of a dog. [ Eng. ] [ 1913 Webster ]

To back and fill, to manage the sails of a ship so that the wind strikes them alternately in front and behind, in order to keep the ship in the middle of a river or channel while the current or tide carries the vessel against the wind. Hence: (Fig.) To take opposite positions alternately; to assert and deny. [ Colloq. ] --
To back out,
To back down, to retreat or withdraw from a promise, engagement, or contest; to recede. [ Colloq. ] [ 1913 Webster ]

Cleon at first . . . was willing to go; but, finding that he [ Nicias ] was in earnest, he tried to back out. Jowett (Thucyd. ) [ 1913 Webster ]

2. 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. [ 1913 Webster ]

3. To a former state, condition, or station; as, to go back to private life; to go back to barbarism. [ 1913 Webster ]

4. (Of time) In times past; ago. “Sixty or seventy years back.” Gladstone. [ 1913 Webster ]

5. Away from contact; by reverse movement. [ 1913 Webster ]

The angel of the Lord . . . came, and rolled back the stone from the door. Matt. xxviii. 2. [ 1913 Webster ]

6. 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. [ 1913 Webster ]

7. In a state of restraint or hindrance. [ 1913 Webster ]

The Lord hath kept thee back from honor. Numb. xxiv. 11. [ 1913 Webster ]

8. In return, repayment, or requital. [ 1913 Webster ]

What have I to give you back? Shak. [ 1913 Webster ]

9. In withdrawal from a statement, promise, or undertaking; as, he took back the offensive words. [ 1913 Webster ]

10. In arrear; as, to be back in one's rent. [ Colloq. ] [ 1913 Webster ]

Back and forth, backwards and forwards; to and fro. --
To go back on, to turn back from; to abandon; to betray; as, to go back on a friend; to go back on one's professions. [ Colloq. ] [ 1913 Webster ]