shorten

verb

• To make shorter; to abbreviate.
• To become shorter.
• To make deficient (as to); to deprive (of).
• To make short or friable, as pastry, with butter, lard, etc.
• To reduce or diminish in amount, quantity, or extent; to lessen.

  "to shorten an allowance of food"

• To take in the slack of (a rope).
• To reduce (sail) by taking it in.