sip

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

• intransitive verb To drink in small quantities.
• intransitive verb To drink from in sips.
• intransitive verb To drink something in sips.
• noun The act of sipping.
• noun A small quantity of liquid sipped.

from The Century Dictionary.

• To drink little by little; take (a liquid) into the mouth in small quantities; imbibe a mouthful at a time.
• To take in gradually by some process analogous to drinking; receive or obtain by sucking, inhaling, absorbing, or the like.
• To drink from by sips.
• To take a sip or sips.
• noun The act of sipping, or drinking by small quantities, as a liquid.
• noun A very small draught; a taste (of a liquid).
• noun Drink; sup.

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

• intransitive verb To drink a small quantity; to take a fluid with the lips; to take a sip or sips of something.
• noun The act of sipping; the taking of a liquid with the lips.
• noun A small draught taken with the lips; a slight taste.
• transitive verb To drink or imbibe in small quantities; especially, to take in with the lips in small quantities, as a liquid.
• transitive verb To draw into the mouth; to suck up.
• transitive verb Poetic To taste the liquor of; to drink out of.

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

• noun A small mouthful of drink
• verb transitive To drink slowly, small mouthfuls at a time
• verb Scotland, US, dated Alternative form of seep.

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

• verb drink in sips
• noun a small drink