Where does “poison-ivy” come from?

poison-ivy (English) comes from English poison, from Middle English poysoun, from Old French poison, from Latin pōtiō, from Latin -tiō, from Latin dissertātiō, from Latin dissertus, from Latin disserere — small stone, pebble; gravel, rubble.

poison-ivy (English): A woody vine plant in the family Anacardiaceae (Toxicodendron radicans or Rhus toxicodendron), well-known for its ability to produce urushiol, a skin irritant that causes an itching rash for most people

Definitions

  1. A woody vine plant in the family Anacardiaceae (Toxicodendron radicans or Rhus toxicodendron), well-known for its ability to produce urushiol, a skin irritant that causes an itching rash for most people

Ancestry of “poison-ivy”, step by step

poison-ivy traces back through two separate lines of ancestry.

via English poison

StepLanguageWordMeaning
1EnglishpoisonA substance that is harmful or lethal to a living...
2Middle EnglishpoysounA poison; a poisonous substance especially as a drink
3Old Frenchpoisonpoison; potion
4Latinpōtiōdrinking
5Latin-tiōtion, -ation, -ing
6Latindissertātiō(spoken) dissertation, discourse, disquisition
7Latindissertusarranged, disposed; explained
8Latindissereresecond-person singular future passive indicative...
9Latindis-asunder, apart, in two; reversal, removal;...
10Latincalceusshoe
11Latincalxlimestone; chalk; the finish line
12Ancient Greekχάλιξsmall stone, pebble; gravel, rubble

via English Ivy

StepLanguageWordMeaning
1EnglishIvyA university that is part of the Ivy League
2Middle Englishiviivy
3Old Englishīfiġivy
4Tagalogibigliking
5Proto-Germanicibahsivy
6Proto-Indo-European(h₁)ebʰ-climbing
Every word from Ancient Greek χάλιξEvery word from Latin -tiōEvery word from Latin dis-
poison-ivy — Etymology, Origin & Word History | Etymology Explorer