perch (n.1)

"rod or pole on which a bird alights and rests," late 13c., originally only "a pole, rod, stick, stake," from Old French perche "unit of linear measurement" (5.5 yards), also "measuring rod, pole, bar" used to measure this length (13c.), from Latin pertica "pole, long staff, measuring rod," which is 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 the 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.

common spiny-finned freshwater fish, c. 1300, perche, from Old French perche, from Latin perca "perch," from Greek perkē "a perch," from perknos "spotted, having dark spots," from PIE root *perk- "speckled, spotted" (source also of Sanskrit prsnih "speckled, variegated;" Greek perkazein "to become dark"), typically in names of animals; compare Middle Irish erc, Welsh erch "spotted, dark red; salmon, trout," also "cow, lizard;" Old High German forhana, Old English forne "trout."

"to roost, to alight or settle on or as on a perch; to occupy some elevated position," late 14c., from Old French perchier "to sit on a perch" (of a bird), from perche (n.); see perch (n.1). Related: Perched; perching.

"measure of land equal to a square lineal perch" (usually 160 to the acre), late 14c., earlier "land-measuring rod" (c. 1300), from Old French perche "unit of linear measurement" (5.5 yards), also "measuring rod, pole, bar" used to measure this length (13c.), from Latin pertica "pole, long staff, measuring rod," which is related to Oscan perek "pole," Umbrian perkaf "twigs, rods." The same word as perch (n.1).