lead (n.1)youdaoicibaDictYouDict[lead 词源字典]
heavy metal, Old English lead, from West Germanic *loudhom (cognates: Old Frisian lad, Middle Dutch loot, Dutch lood "lead," German Lot "weight, plummet"). The name and the skill in using the metal seem to have been borrowed from the Celts (compare Old Irish luaide), probably from PIE root *plou(d)- "to flow."

Figurative of heaviness since at least early 14c. Black lead was an old name for "graphite," hence lead pencil (1680s) and the colloquial figurative phrase to have lead in one's pencil "be possessed of (especially male sexual) vigor," attested by 1902. Lead balloon "a failure," American English slang, attested by 1957 (as a type of something heavy that can be kept up only with effort, from 1904). Lead-footed "slow" is from 1896; opposite sense of "fast" emerged 1940s in trucker's jargon, from notion of a foot heavy on the gas pedal.[lead etymology, lead origin, 英语词源]
step (v.)youdaoicibaDictYouDict
Old English steppan (Anglian), stæppan (West Saxon) "take a step," from West Germanic *stap- "tread" (cognates: Old Frisian stapa, Middle Dutch, Dutch stappen, Old High German stapfon, German stapfen "step"), from PIE root *stebh- "post, stem; to support, place firmly on" (see staff (n.); cognates: Old Church Slavonic stopa "step, pace," stepeni "step, degree"). The notion is perhaps "a treading firmly on; a foothold."

Transitive sense (as in step foot in) attested from 1530s. Related: Stepped; stepping. Originally strong (past tense stop, past participle bestapen); weak forms emerged 13c., universal from 16c. To step out "leave for a short time" is from 1530s; meaning "to go out in public in style" is from 1907. Step on it "hurry up" is 1923, from notion of gas pedal.