Etymology
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inertia (n.)
1713, "that property of matter by virtue of which it retains its state of rest or of uniform rectilinear motion so long as no foreign cause changes that state" [Century Dictionary], introduced as a term in physics 17c. by German astronomer and physician Johann Kepler (1571-1630) as a special sense of Latin inertia "unskillfulness, ignorance; inactivity, idleness," from iners (genitive inertis) "unskilled; inactive" (see inert). Also sometimes vis inertia "force of inertia." Used in 1687 by Newton, writing in Modern Latin. The classical Latin sense of "apathy, passiveness, inactivity" is attested in English from 1822.
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calorie (n.)

unit of heat in physics, 1866, from French calorie, from Latin calor (genitive caloris) "heat," from PIE *kle-os-, suffixed form of root *kele- (1) "warm."

As a unit of energy, defined as "heat required to raise 1 gram of water 1 degree Celsius" (the small or gram calorie), but as a measure of the energy-producing value of food, "heat required to raise 1 kilogram of water 1 degree Celsius" (the large calorie or kilocalorie). In part because of this confused definition, it was largely replaced 1950 in scientific use by the joule. Calorie-counting or -watching as a method of scientific weight-regulation is attested by 1908.

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determination (n.)

mid-14c., determinacioun, "decision, sentence in a suit at law, definite or authoritative judicial settlement," from Old French déterminacion "determination, settlement, definition" (14c.) and directly from Medieval Latin determinationem (nominative determinatio) "conclusion, boundary," noun of action from past-participle stem of Latin determinare "to enclose, bound, set limits to" (see determine).

Meaning "action of definitely ascertaining" is from 1670s; that of "result ascertained, a conclusion" is from 1560s. As "fixed direction toward a goal or terminal point," from 1650s, originally in physics or anatomy; metaphoric sense "fixation of will toward a goal, state of mental resolution with regard to something" is from 1680s; general sense of "quality of being resolute, fixedness of purpose as a character trait" is by 1822.

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nucleus (n.)

1704, "kernel of a nut;" 1708, "head of a comet;" from Latin nucleus "kernel," from nucula "little nut," diminutive of nux (genitive nucis) "nut," from PIE *kneu- "nut" (source also of Middle Irish cnu, Welsh cneuen, Middle Breton knoen "nut," Old Norse hnot, Old English hnutu "nut").

The general sense of "central mass or thing, about which others cluster or matter collects," is from 1762. In biology, "dense, typically rounded structure in a cell, bounded by membranes," from 1831. Later they were found to contain the genetic material. Modern meaning in physics, "positively charged central core of an atom," is from 1912, by Ernest Rutherford, though theoretical use for "central point of an atom" is from 1844, in Faraday.

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induction (n.)
late 14c., "advancement toward the grace of God;" also (c. 1400) "formal installation of a clergyman," from Old French induction (14c.) or directly from Latin inductionem (nominative inductio) "a leading in, introduction, admission," noun of action from past participle stem of inducere "to lead" (see induce).

As a term in logic (early 15c.) it is from Cicero's use of inductio to translate Greek epagoge "leading to" in Aristotle. Induction starts with known instances and arrives at generalizations; deduction starts from the general principle and arrives at some individual fact. As a term in physics, in reference to electrical influence, 1801; military service sense is from 1934, American English. Related: Inductional.
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reaction (n.)

"action in resistance or response to another action or power," 1640s, from re- "back, again, anew" + action (q.v.). Modeled on French réaction, older Italian reattione, from Medieval Latin reactionem (nominative reactio), a noun of action formed in Late Latin from the past-participle stem of Latin reagere "react," from re- "back" + agere "to do, perform."

Originally a word in physics and dynamics. In chemistry, "mutual or reciprocal action of chemical agents upon each other," by 1836. The general sense of "action or feeling in response" (to a statement, event, etc.) is recorded from 1914. Reaction time, "time elapsing between the action of an external stimulus and the giving of a signal in reply," attested by 1874.

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conductor (n.)

1520s, "one who leads or guides," from French conductour (14c., Old French conduitor), from Latin conductor "one who hires, contractor," in Late Latin "a carrier," from conductus, past participle of conducere "to lead or bring together, contribute, serve," from assimilated form of com "with, together" (see con-) + ducere "to lead" (from PIE root *deuk- "to lead").

Earlier in same sense was conduitour (early 15c., from Old French conduitor). Meaning "a director or manager" is from 1630s; specific sense of "leader of an orchestra or chorus" is from 1784. Meaning "one who has charge of passengers and collects fares on a railroad" is 1832, American English. Physics sense of "object or device that passes heat or other energy" is from 1745; of electricity from 1737.

The office of conductor in the modern sense was not clearly distinguished from that of leader until about 1800; formerly the leader played an instrument, usually the harpsichord [Century Dictionary]
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bootstrap (n.)
also boot-strap, tab or loop at the back of the top of a men's boot, which the wearer hooked a finger through to pull the boots on, 1870, from boot (n.1) + strap (n.).

Circa 1900, to pull (oneself) up by (one's) bootstraps was used figuratively of an impossible task (among the "practical questions" at the end of chapter one of Steele's "Popular Physics" schoolbook (1888) is, "30. Why can not a man lift himself by pulling up on his boot-straps?" and an excellent question it is). By 1916 the meaning of the phrase had expanded to include "better oneself by rigorous, unaided effort." The meaning "fixed sequence of instructions to load the operating system of a computer" (1953) is from the notion of the first-loaded program pulling itself (and the rest) up by the bootstrap. It was used earlier of electrical circuits (1946).
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conduct (v.)
Origin and meaning of conduct

early 15c., "to guide, accompany and show the way," from Latin conductus, past participle of conducere "to lead or bring together; contribute, serve," from assimilated form of com "with, together" (see con-) + ducere "to lead" (from PIE root *deuk- "to lead").

Sense of "to lead, command, direct, manage" is from mid-15c., originally military. General meaning "to direct, manage, act as leader of" is from 1630s; especially of a musical performance (1791).

Meaning "behave in a certain way" is from 1710. In physics, "to carry, convey, transmit," 1740. Related: Conducted; conducting. An earlier verb in the same sense was condyten (c. 1400), which goes with conduit.

To conduct is to lead along, hence to attend with personal supervision; it implies the determination of the main features of administration and the securing of thoroughness in those who carry out the commands; it is used of both large things and small, but generally refers to a definite task, coming to an end or issue: as, to conduct a religious service, a funeral, a campaign. [Century Dictionary]
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pressure (n.)

late 14c., "suffering, anguish; act or fact of pressing on the mind or heart," from Old French presseure "oppression; torture; anguish; press" (for wine or cheeses), "instrument of torture" (12c.) and directly from Latin pressura "action of pressing," from pressus, past participle of premere "to press, hold fast, cover, crowd, compress" (from PIE root *per- (4) "to strike").

The literal meaning "act or fact of pressing" in a physical sense is attested in English from early 15c. The meaning "moral or mental coercing force, exertion of authority or influence" is from 1620s; the meaning "urgency, demand on one's time or energies" is from 1812. Scientific sense in physics, "force per unit area exerted over a surface and toward the interior" is from 1650s.

Pressure cooker "airtight vessel in which food is cooked in steam under pressure" is attested from 1915; figurative sense is from 1958. Pressure point of the skin is attested from 1876. Pressure-treated, of woods impregnated with a preservative fluid under pressure, is from 1911.

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