1. se-- : apart from ; word-forming element, from Latin se-, collateral form of sed- "without, apart, aside, on one's own," related to sed, Latin reflexive pronoun (accusative and ablative), from PIE *sed-, extended form of root *s(w)e-, pronoun of the third person and reflexive (source also of German sich; see idiom).

2. xerox : 1952, trademark taken out by Haloid Co. of Rochester, N.Y., for a copying device, from xerography. The verb is first attested 1965, from the noun, despite strenuous objection from the Xerox copyright department. Related: Xeroxed; Xeroxing.

3. hydr-- : about water ; hydro-- : before vowels hydr-, word-forming element in compounds of Greek origin, meaning "water," from Greek hydro-, comb. form of hydor "water" (see water (n.1)). Also sometimes a comb. form of hydrogen.

4. pan-- : word-forming element meaning "all, every, whole, all-inclusive," from Greek pan-, combining form of pas (neuter pan, masculine and neuter genitive pantos) "all," from PIE *pant- "all" (with derivatives found only in Greek and Tocharian). 
               Commonly used as a prefix in Greek, in modern times often with nationality names, the first example of which seems to have been Panslavism (1846). Also panislamic (1881), pan-American (1889), pan-German (1892), pan-African (1900), pan-European (1901), pan-Arabism (1930).

5. evacuate : (v.) 1520s (trans.), from Latin evacuatus, past participle of evacuare "to empty, make void, nullify," used by Pliny in reference to the bowels, used figuratively in Late Latin for "clear out;" from assimilated form of ex- "out" (see ex-) + vacuus "empty" (see vacuum).

Earliest sense in English is medical. Military use is by 1710. Meaning "remove inhabitants to safer ground" is from 1934. Intransitive sense is from 1630s; of civilian persons by 1900. Replaced Middle English evacuen "draw off or expel (humors) from the body" (c. 1400). Related: Evacuated; evacuating.

6. evaporate : (v.) early 15c., "draw off (humors or spirits) as vapor," from Late Latin evaporatum, past participle of evaporare "disperse in vapor" (see evaporation). Intransitive sense by 1560s. Figurative use by 1610s. Related: Evaporated; evaporating.

7. --gen : word-forming element technically meaning "something produced," but mainly, in modern use, "thing that produces or causes," from French -gène (18c.), from Greek -genes "born of, produced by," which is from the same source as genos "birth," genea "race, family," from PIE *gene- (see genus). First used in late 18th century French chemistry (see oxygen), it probably involves a misunderstanding of -genes, as though it meant "that which produces."