Definition of rumen in English:


nounrumens, rumina

  • The first stomach of a ruminant, which receives food or cud from the oesophagus, partly digests it with the aid of bacteria, and passes it to the reticulum.

    • ‘When calves are fed milk it is funnelled through the oesophageal groove to the true stomach, bypassing the rumen.’
    • ‘So mammals are unable to digest cellulose, except some ruminants that have cellulase-secreting bacteria in their rumens.’
    • ‘He was interested in improving digestive processes within the rumen, the first of the four stomachs of ruminant animals, where cellulose is broken down by bacteria.’
    • ‘Added fat at levels at or above 5% of the diet has been reported to impair fiber digestion in the rumen and to depress feed intake.’
    • ‘Energy from the grain apparently helps complete the conversion of nitrate to bacterial protein in the rumen.’


Early 18th century from Latin, literally ‘throat’.