The Collaborative International Dictionary of English v.0.48:

Ingestion \In*ges"tion\, n. [L. ingestio: cf. F. ingestion.]
   (Physiol.)
   The act of taking or putting into the stomach; as, the
   ingestion of milk or other food.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ingestion
    n 1: the process of taking food into the body through the mouth
         (as by eating) [syn: consumption, ingestion, intake,
         uptake]

Moby Thesaurus II by Grady Ward, 1.0:

96 Moby Thesaurus words for "ingestion":
   ablation, absorption, appetite, assimilation, attrition, bile,
   burning up, cannibalism, carnivorism, carnivority, carnivorousness,
   chewing, consumption, cropping, deglutition, depletion, devouring,
   devourment, dieting, digestion, digestive system, dining, drain,
   drinking, eating, eating up, engorgement, engulfment, epulation,
   erosion, exhaustion, expending, expenditure, feasting, feeding,
   finishing, gastric juice, gastrointestinal tract, gluttony,
   gobbling, grazing, gulp, gulping, herbivorism, herbivority,
   herbivorousness, hunger, imbibing, imbibition, impoverishment,
   ingurgitation, intestinal juice, licking, liver, manducation,
   mastication, messing, munching, nibbling, nutrition, omnivorism,
   omnivorousness, omophagy, pancreas, pancreatic digestion,
   pancreatic juice, pantophagy, pasture, pasturing, pecking,
   predigestion, regalement, relishing, rumination, saliva,
   salivary digestion, salivary glands, savoring, secondary digestion,
   slurp, soaking-up, spending, squandering, swallow, swallowing,
   taking-in, tasting, using up, vegetarianism, wastage, waste,
   wastefulness, wasting away, wearing away, wearing down, wolfing