Source : Webster's Revised Unabridged Dictionary (1913)

Sip \Sip\, v. t. [imp. & p. p. {Sipped}; p. pr. & vb. n.
   {Sipping}.] [OE. sippen; akin to OD. sippen, and AS. s?pan to
   sip, suck up, drink. See {Sup}, v. t.]
   1. To drink or imbibe in small quantities; especially, to
      take in with the lips in small quantities, as a liquid;
      as, to sip tea. ``Every herb that sips the dew.''
      --Milton.

   2. To draw into the mouth; to suck up; as, a bee sips nectar
      from the flowers.

   3. To taste the liquor of; to drink out of. [Poetic]

            They skim the floods, and sip the purple flowers.
                                                  --Dryden.

Source : WordNet®

sip
     n : a small drink [syn: {nip}]
     [also: {sipping}, {sipped}]

sip
     v : drink in sips; "She was sipping her tea"
     [also: {sipping}, {sipped}]

sipping
     See {sip}