English has a lot of words which are based on Greek prefixes. Two of the interesting Greek prefixes are “hyper” which means “over, above, excessive, extreme” and “hypo” which means “under, beneath, below.”
Hyper-
The prefix “hyper-” has been used to create a number of English words:
Hyperbole: the “bole” in “hyperbole” comes from “ballien” which means “to throw.” Thus the deep meaning of “hyperbole” is to “throw over” the line of credibility. The slang version of “hyperbole” is “hype” which began to appear in the 1960s.
Hypertext: this word entered into English in 1965. It was originally coined by T.H. Nelson, a computer engineer, to describe a system of hardware and software that allows for movement between text, sound, and graphics. With regards to etymology, the “text” in “hypertext” comes from the Latin “texere” which means “to weave.”
Hyperborean: Boreas was the Greek god of the North Wind. Thus “hyperborean” refers to the far north.
Hypergamy: The “gamy” in “hypergamy” is also found in “bigamy” and “polygamy” and comes from “gamos” meaning “marriage.” Thus “hypergamy” refers to marriage above an individual’s class or position in society.
Hypermnesia: The “mnesia” in “hypermnesia” comes from “mimneskesthai” which means “to recall.” Thus “hypermnesia” refers to an abnormally acute memory, an unusual power recollection.
Hypo-
Like “hyper-”, the prefix “hypo-” has been used to create a number of English words:
Hypodermic: The “dermic” in “hypodermic” comes from “derm” meaning “skin.” Thus, the deep meaning of “hypodermic” means “under the skin.” As most people are aware, hypodermic injections are always administered under the skin.
Hypochondria: The “chondria” in “hypochondria” comes from “khondros” which means “cartilage.” A few centuries ago the hypochondria—“below the cartilage”—referred to the area of the abdomen beneath the ribs, an area which was supposed to be the source of morbidity and melancholy. In the 17th century “hypochondria” referred to “depression.” By the 19th century, its meaning had evolved into “the belief of being ill.”
Hypothermia: The “thermia” in “hypothermia” is also found in “thermometer” and “thermostat” and comes from “therme” which means “heat.” Thus “hypothermia” has come to refer to a below-normal body temperature.
Hypothesis: The hypothesis is, of course, the assumption or supposition that supports the reasoning of the thesis. Thus is “underlies” the thesis.
Hypocaust: The “caust” in “hypocaust” comes from “kaien” which means “to burn.” Hypocaust refers to the series of channels under the floors of Roman buildings. These channels conducted heat from a furnace.
Hypotenuse: I suspect that anyone who has taken a geometry class has at least some vague recollections of the hypotenuse as the side of a right-angle triangle opposite the right angle. The “teneuse” comes from “teinein” meaning “to stretch.” The hypotenuse thus “stretches under” (i.e. lies opposite) the right angle.
Hypocrite: The “crite” in “hypocrite” comes from “krínein” which means “separate.” Originally, the word meant “separate gradually” and eventually it came to be used in drama to refer to “answer another actor on stage” or “to play a part.”