back

The rear of the body, especially the part between the neck and the end of the spine and opposite the chest and belly.

“Could you please scratch my back?”

That which is farthest away from the front.

“He sat in the back of the room.”

Upper part of a natural object which is considered to resemble an animal's back.

“The small boat raced over the backs of the waves.”

A support or resource in reserve.

The keel and keelson of a ship.

“The ship's back broke in the pounding surf.”

The roof of a horizontal underground passage.

Effort, usually physical.

“Put some back into it!”

A non-alcoholic drink (often water or a soft drink), to go with hard liquor or a cocktail.

“Could I get a martini with a water back?”

Among leather dealers, one of the thickest and stoutest tanned hides.

To go in the reverse direction.

“the train backed into the station;  the horse refuses to back”

To support.

“I back you all the way;  which horse are you backing in this race?”

(of the wind) To change direction contrary to the normal pattern; that is, to shift anticlockwise in the northern hemisphere, or clockwise in the southern hemisphere.

(of a square sail) To brace the yards so that the wind presses on the front of the sail, to slow the ship.

(of an anchor) To lay out a second, smaller anchor to provide additional holding power.

(of a hunting dog) To stand still behind another dog which has pointed.

To push or force backwards.

“The mugger backed her into a corner and demanded her wallet.”

To get upon the back of; to mount.

To place or seat upon the back.

To make a back for; to furnish with a back.

“to back books”

To adjoin behind; to be at the back of.

To write upon the back of, possibly as an endorsement.

“to back a letter;  to back a note or legal document”

(of a justice of the peace) To sign or endorse (a warrant, issued in another county, to apprehend an offender).

To row backward with (oars).

“to back the oars”

Near the rear.

“Go in the back door of the house.”

Not current.

“I’d like to find a back issue of that magazine.”

Far from the main area.

“They took a back road.”

In arrear; overdue.

“They still owe three months' back rent.”

Moving or operating backward.

“back action”

Pronounced with the highest part of the body of the tongue toward the back of the mouth, near the soft palate (most often describing a vowel).

“The vowel of lot has a back vowel in most dialects of England.”

To or in a previous condition or place.

“He gave back the money.   He needs his money back.   He was on vacation, but now he’s back.   The office fell into chaos when you left, but now order is back.”

Away from the front or from an edge.

“Sit all the way back in your chair.”

In a manner that impedes.

“Fear held him back.”

In a reciprocal manner; in return.

“If you hurt me, I'll hurt you back.”

Earlier, ago.

“I last saw him a day or two back.”