"arched fire chamber for heating rooms above via pipes," 1670s, from Late Latin hypocaustum, from Greek hypokauston, literally "heated from below," from hypo- "under; up from under.”

The word "holocaust" originally derived from the Koine Greek word holokauston, meaning "a completely (holos) burnt (kaustos) sacrificial offering," or "a burnt sacrifice offered to a god." In Hellenistic religion, gods of the earth and underworld received dark animals, which were offered by night and burnt in full.

1877, Modern Latin, from hypo- "under" + Greek therme "heat"  ("to heat, warm").

c. 1200, ypocrite, "false pretender to virtue or religion," from Old French ypocrite (12c., Modern French hypocrite), from Church Latin hypocrita "a hypocrite," from Greek hypokritēs "stage actor; pretender, dissembler."

1896, coined 1893 in German from Greek hypo- "under" + thalamus.

the side of a right triangle that is opposite the right angle, 1570s, from Late Latin hypotenusa, from Greek hypoteinousa "stretching under" (the right angle).

in grammar, "dependent construction" (opposed to parataxis).

1590s, "a particular statement;" 1650s, "a proposition, assumed and taken for granted, used as a premise," from French hypothese and directly from Late Latin hypothesis, from Greek hypothesis "base, groundwork, foundation," hence in extended use "basis of an argument, supposition," literally "a placing under," from hypo- "under" + thesis "a placing, proposition"

"having reduced tension or pressure," 1873.

1941, from hypo- + oxygen + abstract noun ending -ia. Related: Hypoxic.