frog (n.1) Look up frog at Dictionary.com
Old English frogga, a diminutive of frox, forsc, frosc "frog," from Proto-Germanic *fruska-z (cognates: Old Norse froskr, Middle Dutch vorsc, German Frosch "frog"), probably literally "hopper," from PIE root *preu- "to hop" (cognates: Sanskrit provate "hops," Russian prygat "to hop, jump").

The Latin word (rana) is imitative of croaking. Collateral Middle English forms frude, froud are from Old Norse frauðr "frog," and frosk "frog" survived in English dialects into the 19c.
I always eat fricasseed frogs regretfully; they remind one so much of miniature human thighs, and make one feel cannibalistic and horrid .... [H. Ellen Brown, "A Girl's Wanderings in Hungary," 1896]
As a derogatory term for "Frenchman," 1778 (short for frog-eater), but before that (1650s) it meant "Dutch" (from frog-land "marshy land"). To have a frog in the throat "be hoarse" is from 1892, from the "croaking" sound.
frog (n.2) Look up frog at Dictionary.com
fastening for clothing, 1719, originally a belt loop for carrying a weapon, of unknown origin; perhaps from Portuguese froco, from Latin floccus "flock of wool."