eructation

n. burping, belching; violent expulsion

Burping, also known as belching, ructus, or eructation is the release of gas from the digestive tract (mainly esophagus and stomach) through the mouth. It is often accompanied with a typical sound and sometimes an odor.
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n. eructation

(n.)
The act of belching wind from the stomach; a belch.
  

(n.)
A violent belching out or emitting, as of gaseous or other matter from the crater of a volcano, geyser, etc.
  

Noun
1. (of volcanos) pouring out fumes or lava (or a deposit so formed)
(synonym) eruption, extravasation
(hypernym) action, activity, activeness
(derivation) spew, spew out, eruct
(classification) vent, volcano
2. a reflex that expels wind noisily from the stomach through the mouth
(synonym) belch, belching, burp, burping
(hypernym) reflex, instinctive reflex, innate reflex, inborn reflex, unconditioned reflex, physiological reaction
(derivation) burp, bubble, belch, eruct