word-forming element in science meaning "thick, large, massive," from Latinized form of Greek pakhys "thick, fat, well-fed, dense, stout,"  from PIE *bhengh- "thick, fat" (source also of Sanskrit bahu- "much, numerous;" Avestan bazah- "height, depth;" Armenian bazum "much;" Hittite pankush "large," panku- (adj.) "total;" Old Norse bingr "heap," Old High German bungo "a bulb;" Latvian biezs "thick").

in zoology, "thick-headed," by 1862, from pachy- "thick, large" + -cephalic. Related: Pachycephalous (1890).

1838, from French pachyderme (c. 1600), adopted as a biological term for non-ruminant hoofed quadrupeds 1797 by French naturalist Georges Léopole Chrétien Frédéric Dagobert, Baron Cuvier (1769-1832), from Greek pakhydermos "thick-skinned," from pakhys "thick, large, massive" (see pachy-) + derma "skin" (from PIE root *der- "to split, flay, peel," with derivatives referring to skin and leather). Cuvier's order of Pachydermata is now disused in zoology, but pachyderm remains in common use to describe elephants, rhinoceroses, hippopotamuses, etc. Related: Pachydermal; pachydermic; pachydermatous.

genus of small, evergreen plants, 1813, from Modern Latin (Andre Michaux, 1803), from Greek pakhys "thick" (see pachy-) + anēr (genitive andros) "man" (from PIE root *ner- (2) "man"), which is used in botany to mean "stamen, having stamens" (the plant is notable for its four stamens).

1540s, "tending to make peace, concillatory," from Middle French pacifique, from Latin pacificus "peaceful, peace-making," from pax (genitive pacis) "peace" (see peace) + combining form of facere "to make" (from PIE root *dhe- "to set, put"). Meaning "peaceful, characterized by peace or calm" is recorded from 1630s. Related: Pacifical (mid-15c., "of a peaceful nature"); pacifically.

Pacific, making or desiring to make peace; peaceable, desiring to be at peace, free from the disposition to quarrel; peaceful, in a state of peace. [Century Dictionary, 1895]

The Pacific Ocean (1660 in English) was famously so called in 1519 by Magellan when he sailed into it and found it calmer than the stormy Atlantic, or at least calmer than he expected it to be. According to an original account of the voyage by an Italian named Pigafetta, who was among the adventurers, Magellan gave the entrance to what Pigafetta calls "the South Sea" the Latin name Mare Pacificum.  The U.S. Pacific Northwest is so called by 1889.

"a setting at peace," mid-15c., pacificacioun, from Old French pacification "act of making peaceful" (15c.) and directly from Latin pacificationem (nominative pacificatio) "a peace-making," noun of action from past-participle stem of pacificare "to pacify" (see pacify). As "military operation designed to secure local cooperation in an area where enemy forces are thought to be active," by 1946.

1904, "pacifism, rejection of war and violence as a matter of principle," 1904, from pacific + -ism. Fowler, in 1926, wrote that the longer form was better, "but its chances of ousting the wrong form are small."

But pacificism gradually evolved a sense distinct from pacifism, "advocacy of a peaceful policy as a first resort or in a particular instance." Since the 19th century the international peace movement has included absolutists (who believe war can be totally and immediately repudiated) and moderates who see the abolition of war as a gradual process of promoting international systems and reforming nations and who believe that, until then, defensive military force may be needed to protect reforms. The use of pacificist for the latter was suggested in 1957 by British historian and nuclear-disarmament activist A.J.P. Taylor. Related: Pacificist.

1530s, "one who pacifies or appeases," agent noun from pacify. The meaning "nipple-shaped device for babies" is recorded by 1904. Pacificator "a peacemaker" (1530s) is directly from Latin.

"policy or doctrine of rejecting war and violence in solving disputes," especially in international affairs, 1902, from French pacifisme (1901), which was apparently coined by French anti-war writer Émile Arnaud (1864-1921), from pacifique (see pacific).

"proponent or advocate of pacifism," 1903, from French pacifiste (see pacifism). Related: Pacifistic (1902).