MeSH definition : A thin-walled, glandular stomach found in birds. It precedes the gizzard.;
MeSH annotation : avian only; non-avian: use DIGESTIVE SYSTEM; dis: coord IM with STOMACH DISEASES /vet
(IM); neopl: coord IM with STOMACH NEOPLASMS /vet (IM) histol type (IM);
Wikipedia link : https://en.wikipedia.org/wiki/Proventriculus;