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dare: dare: [OE] Dare used to be a widespread Germanic verb, with relatives in Old High German (giturran) and Gothic (gadaursan), but today it survives only in English (the similarlooking Danish turde and Swedish töras are probably not related). It comes via Germanic *ders- from an Indo-European *dhers-, which also produced Greek thrasús ‘bold’ and Old Slavic druzate ‘be bold’.

In Old English it was a conjugationally complex verb, with anomalous present and past forms, but most of its oddities have now been ironed out: the past form durst is now on its last legs, and only the 3rd present singular form remains unusual, especially in negative contexts and questions: she daren’t rather than she dares not.
environ (v.): late 14c. (implied in environing), "to surround, encircle, encompass," from Old French environer "to surround, enclose, encircle," from environ "round about," from en- "in" (see en- (1)) + viron "a circle, circuit," also used as an adverb, from virer "to turn" (see veer). Related: Environed.
environment (n.): c. 1600, "state of being environed" (see environ + -ment); sense of "the aggregate of the conditions in which a person or thing lives" first recorded 1827 (used by Carlyle to render German Umgebung); specialized ecology sense first recorded 1956.
iron (v.): c. 1400, irenen, "to make of iron," from iron (n.). Meaning "press clothes" (with a heated flat-iron) is recorded from 1670s. Related: Ironed; ironing.