Definition of "hypo-" [hy•po-]

• Below; beneath; under: hypodermic. (prefix)
• Less than normal; deficient: hypoesthesia. (prefix)
• In the lowest state of oxidation: hypoxanthine. (prefix)

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.

• "You also may experience hypo- or hyper-pigmentation, where patches of your skin may appear lighter or darker than surrounding areas."
• "Some scars present as post-inflammatory hypo- or hyperpigmentation PIH."
• "Dark skin types (Fitzpatrick Types 5 and 6) should stay away from IPL and pigment-targeting lasers such as the Nd:YAG, since they can cause postinflammatory hypo- or hyperpigmentation (PIH)."