islets of Langerhans is·let·sof·langerhans uncommon noun 1. cell clusters in the pancreas that form the endocrine part of that organ; secrete insulin and other hormones Synonymsislands of Langerhansisles of Langerhansislets of Langerhans Related words Broader terms endocrine gland Parts pancreas WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.