from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A peptide hormone neurotransmitter produced by fat cells and involved in the regulation of appetite.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A protein hormone produced in adipose tissue; it plays a role in regulating appetite and metabolism.
Ancient Greek λεπτός ("thin") + -in (Wiktionary)