Word Origin & History
"where a bird rests," late 13c., "a pole, rod, stick, stake," from O.Fr. perche "unit of linear measurement" (5.5 yards), also "measuring rod, pole, bar" used to measure this length (13c.), from L. pertica "pole, long staff, measuring rod," related to Oscan perek "pole," Umbrian perkaf "twigs, rods."
Meaning "a bar fixed horizontally for a hawk or tame bird to rest on" is attested from late 14c.; this led to general sense of "any thing that any bird alights or rests on" (late 15c.). Figurative sense of "an elevated or secure position" is recorded from 1520s. The verb is first recorded late 14c., from the noun. The "land-measuring rod" sense also was in M.E., hence surviving meaning "measure of land equal to a square lineal perch" (usually 160 to the acre), mid-15c.
"spiny-finned freshwater fish," c.1300, from O.Fr. perche, from L. perca "perch," from Gk. perke, from PIE base *perk-/*prek- "speckled, spotted" (cf. Skt. prsnih "speckled, variegated;" Gk. perknos "dark-colored," perkazein "to become dark").