c. 1400, "active or secular life," from Old French activité, from Medieval Latin activitatem (nominative activitas), a word in Scholastic philosophy, from Latin activus "active" (see active). The meaning "state of being active, briskness, liveliness" is recorded from 1520s; that of "capacity for acting on matter" is from 1540s. As "an educational exercise," by 1923.
1590s, "conception, mental scheme," from Late Latin theoria (Jerome), from Greek theōria "contemplation, speculation; a looking at, viewing; a sight, show, spectacle, things looked at," from theōrein "to consider, speculate, look at," from theōros "spectator," from thea "a view" (see theater) + horan "to see," which is possibly from PIE root *wer- (3) "to perceive." Philosophy credits sense evolution in the Greek word to Pythagoras.
Earlier in this sense was theorical (n.), late 15c. Sense of "principles or methods of a science or art" (rather than its practice) is first recorded 1610s (as in music theory, which is the science of musical composition, apart from practice or performance). Sense of "an intelligible explanation based on observation and reasoning" is from 1630s.
"action of converting (something) into a commercial product or activity," 1968, from commodity + -fication "a making or causing." Originally in Marxist political theory, "the assignment of a market value," often to some quality or thing that the user of the word feels would be better off without it.
1610s, "contemplative," with -al (1) + Late Latin theoreticus "of or pertaining to theory," from Greek theoretikos "contemplative, speculative, pertaining to theory" (by Aristotle contrasted to praktikos), from theoretos "that may be seen or considered," from theorein "to consider, look at" (see theory). Meaning "pertaining to theory, making deductions from theory not from fact" (opposed to practical) is from 1650s; earlier in this sense was theorical (c. 1500). Meaning "ideal, hypothetical" is from 1790s (implied in theoretically). Related: theoretician.
Creole French, "party," from zouker "engage in unrestrained social activity."
"pushing activity; activity in the interest of success," 1891, American English, from hustle (v.) in its later colloquial senses; earlier the noun meant "a shaking together" (1715). Sense of "a swindle, illegal business activity" is by 1963, American English. As the name of a popular dance, by 1975.
variant of encase.
Theory of Incasement, an old theory of reproduction which assumed that when the first animal of each species was created, the germs of all other individuals of the same species which were to come from it were incased in its ova. The discovery of spermatozoa developed the theory in two opposite directions: the ovulists, or ovists, held still to the theory of incasement in the female while the animalculists, or spermists, entertained the theory of incasement in the male. [Century Dictionary]