poppy: [OE] The Latin word for ‘poppy’ was papāver. A post-classical descendant, *papāvum, was borrowed into prehistoric West Germanic as *papau. This was later altered to *papāg, which became Old English popæg, ancestor of modern English poppy. Italian papavero ‘poppy’ is a reminder of the Latin word.
poppy (n.)
late Old English popig, popæg, from West Germanic *papua-, probably from Vulgar Latin *papavum, from Latin papaver "poppy," perhaps a reduplicated form of imitative root *pap- "to swell." Associated with battlefields and war dead at least since Waterloo (1815). Poppy-seed is from early 15c.; in 17c. it also was a small unit of length (less than one-twelfth of an inch).