Where does “Perseus Arm” come from?

Perseus Arm (English) comes from English Arm, from Middle English arm, from Old English earm, from Proto-West Germanic arm, from Proto-Germanic armaz, from Proto-Indo-European h₂ermos, from Proto-Indo-European h₂er- — to fit, to fix, to put together.

Ancestry of “Perseus Arm”, step by step

Perseus Arm traces back through two separate lines of ancestry.

via English Arm

StepLanguageWordMeaning
1EnglishArmAbbreviation of Armenian
2Middle Englisharmarm; poor; miserable, wretched
3Old Englishearmarm; poor, miserable
4Proto-West Germanicarmarm; poor, miserable; pitiful, pitiable
5Proto-Germanicarmazarm; poor, miserable; pitiful, pitiable
6Proto-Indo-Europeanh₂ermos
7Proto-Indo-Europeanh₂er-to fit, to fix, to put together

via English Perseus

StepLanguageWordMeaning
1EnglishPerseusThe mythological Greek warrior who slew the Gorgon Medusa by decapitating her. He married Andromeda after rescuing her from Ceto and founded Mycenae. He was the son of Zeus and Danae
2LatinPerseusPerseus son of Jupiter and Danae, killed Medusa and rescued Andromeda
3Ancient GreekΠερσεύςPerseus
4Ancient Greekπέρθωto sack, ravage, destroy (a city); to slay (a person)
5Proto-Indo-Europeanbʰerdʰ-to cut; cut
Every word from Proto-Indo-European h₂er-
Perseus Arm — Etymology, Origin & Word History | Etymology Explorer