Source : Webster's Revised Unabridged Dictionary (1913)

Nausea \Nau"se*a\ (? or ?), n. [L., fr. Gr. ?, fr. ? ship. See
   {Nave} of a church, and cf. {Noise}.]
   Seasickness; hence, any similar sickness of the stomach
   accompanied with a propensity to vomit; qualm; squeamishness
   of the stomach; loathing.

Source : WordNet®

nausea
     n 1: the state that precedes vomiting [syn: {sickness}]
     2: disgust so strong it makes you feel sick