Definition of "retinoid" [ret•i•noid]

• Any of various natural or synthetic derivatives of vitamin A. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "If a hormone-based acne treatment isn't an option, consider incorporating a cream called a retinoid (such as Retin-A, Differin or Tazorac) into your skin-care regimen."
• "If you're using "photosensitizing topical or oral medications, such as antibiotics or retinoid products it is even more important to practice this basic step," she says."
• "The doctor should usually start with a topical antibiotic either alone or combined with a topical retinoid, which helps unclog pores."