1847, "derangement of the mental functions," from psycho- + -pathy, on the model of German Psychopathie. First attested in a translation of Feuchtersleben's "Lehrbuch der ärztlichen Seelenkunde" (1845). By 1891 as "cure of sickness by psychic influence or means" (hypnotism, etc.).

1820, from Greek taxis "arrangement, an arranging, the order or disposition of an army, battle array; order, regularity" (see tactics) + derma "skin" (from PIE root *der- "to split, flay, peel," with derivatives referring to skin and leather). Related: Taxidermist (1827).

word-forming element meaning "tree," from Greek dendron "tree," sometimes especially "fruit tree" (as opposed to hylē "timber"), from PIE *der-drew-, from root *deru- "to be firm, solid, steadfast," also forming words for "wood, tree."

word-forming element meaning "of or pertaining to skin," from Greek dermat-, from derma "(flayed) skin, leather," from PIE root *der- "to split, flay, peel," with derivatives referring to skin and leather. The shortened form derm- was used from mid-19c. but is considered incorrect.

"natural marking found on some stones in the form of branching shrubs, trees, or mosses," 1745, from Greek dendrites "of or pertaining to a tree," from dendron "tree," from PIE *der-drew-, from root *deru- "to be firm, solid, steadfast," also forming words for "wood, tree."

"supercontinent of the late Paleozoic era," 1924, from Greek pan- "all" (see pan-) + gaia "earth" (see Gaia). First attested in German, 1920, in Alfred Wegener's "Die Entstehung der Kontinente und Ozeane" (but according to OED the word is not found in 1914 first edition).

late 14c., "walk heavily, stamp," from Middle Low German trampen "to stamp," from Proto-Germanic *tremp- (source also of Danish trampe, Swedish trampa "to tramp, stamp," Gothic ana-trimpan "to press upon"), from PIE *der- (1) "to run, walk, step" (see tread (v.)). Related: Tramped; tramping.

shrub much cultivated for its profuse, handsome flowers, also noted for its leathery evergreen leaves, 1660s, from French rhododendron and directly from Latin rhododendron, from Greek rhododendron, etymologically "rose-tree," from rhodon "rose" (see rose (n.1)) + dendron "tree" (from PIE *der-drew-, from root *deru- "to be firm, solid, steadfast," also forming words for "wood, tree").

"chronic non-inflammatory skin condition which presents in hard patches on the skin," 1865, Modern Latin, from Latinized form of Greek sklēros "hard" (see sclero-) + derma "skin" (from PIE root *der- "to split, flay, peel," with derivatives referring to skin and leather). Also sclerodermia. Related: Sclerodermatous; sclerodermic; sclerodermatic.

1834, from Modern Latin Echinodermata, name of the phylum that includes starfish and sea urchins, from Latinized form of Greek ekhinos "sea urchin," originally "porcupine, hedgehog" (see echidna) + derma (genitive dermatos) "skin," from PIE root *der- "to split, flay, peel," with derivatives referring to skin and leather. So called from its spiky shell. Related: Echinodermal.