ret·i·no·ic acid (rĕt'n-ō'ĭk)
n. In both senses also called tretinoin, vitamin A acid.

1. 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.
2. A preparation of this, used topically to treat acne and to modify the appearance of fine wrinkles, hyperpigmentation, and roughness of facial skin.

[RETIN(OL) + -OIC.]

---

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.

---