from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A vitamin A derivative, C20H28O2, that is a regulator substance in morphogenesis and functions in the growth and development of bone and the maintenance of epithelium.
- n. A preparation of this, used topically to treat acne and to modify the appearance of fine wrinkles, hyperpigmentation, and roughness of facial skin.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A derivative of vitamin A, used in the treatment of acne; it is essential for bone and tissue development.
from the GNU version of the Collaborative International Dictionary of English
- n. A retinoid compound (C20H28O2), closely related to vitamin A. It is also called tretinoin and vitamin A acid.
retin(ol) + -oic.(American Heritage® Dictionary of the English Language, Fourth Edition)