halve

from The American Heritage® Dictionary of the English Language, 5th Edition.

• transitive verb To divide (something) into two equal portions or parts.
• transitive verb To lessen or reduce by half.
• transitive verb Informal To share (something) equally.
• transitive verb Sports To play (a golf game or hole) using the same number of strokes as one's opponent.

from The Century Dictionary.

• To divide into two parts, especially two equal parts or halves.
• To join, as two pieces of timber, by cutting away one half or an equal portion in depth of each, so as to let them into each other.
• noun An obsolete variant of half.

from the GNU version of the Collaborative International Dictionary of English.

• noun obsolete A half.
• transitive verb To divide into two equal parts; ; to be or form half of.
• transitive verb (Arch.) To join, as two pieces of timber, by cutting away each for half its thickness at the joining place, and fitting together.
• transitive verb Of a hole, match, etc., to reach or play in the same number of strokes as an opponent.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb transitive To reduce to half the original amount.
• verb transitive To divide into two halves.
• verb transitive To make up half of.
• verb architecture, transitive To join two pieces of timber etc. by cutting away each for half its thickness at the joining place, and fitting together.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb divide by two; divide into halves