rod: [12] It seems likely that rod is related to English rood [OE]. In post-Anglo-Saxon times this has mainly been used for ‘cross of Christ’, and it now survives mainly in rood screen ‘altar screen’, but in the Old English period it was also used for ‘rod’. Where their Germanic ancestor, which also produced German rute ‘rod’ and Norwegian dialect rodda ‘stake’, came from is not clear. The use of rod for a unit of measurement dates from the mid 15th century. => rood
rod (n.)
Old English rodd "a rod, pole," which is probably cognate with Old Norse rudda "club," from Proto-Germanic *rudd- "stick, club," from PIE *reudh- "to clear land."
As a long, tapering elastic pole for fishing, from mid-15c. Figurative sense of "offshoot" (mid-15c.) led to Biblical meaning "scion, tribe." As an instrument of punishment, attested from mid-12c.; also used figuratively for "any sort of correction or punishment," but the basic notion is of beating someone with a stick.
As a unit of measure (5? yards or 16? feet, also called perch or pole) first attested mid-15c., from the stick used to measure it off. As a measure of area, "a square perch," from late 15c., the usual measure in brickwork. Meaning "light-sensitive cell in a retina" is from 1866, so-called for its shape. Slang meaning "penis" is recorded from 1902; that of "gun, revolver" is from 1903.
例文
1. The rod bent double，the reel shrieked and ratcheted.