The story
Initialism, from amine precursor uptake and decarboxylase; named by the scientist A. G. E. Pearse, who developed the concept in the early 1960s.
Etymology from Wiktionary, CC BY-SA 4.0.
APUD cell
Today it means: Any of a group of endocrine cells that share the function of secreting a low-molecular-weight polypeptide hormone. Full definition →