tinder (n.)

c. 1200, cundel, "to set fire to, to start on fire," probably from a Scandinavian source akin to Old Norse kynda "to kindle, to light a fire," Swedish quindla "kindle," all of uncertain origin, + frequentative suffix -le. Figurative use (of feelings, passions, etc.) is from c. 1300. Intransitive sense "to begin to burn, to catch fire" is from c. 1400. Related: Kindled; kindling.

Modern sources do not connect it to Latin candela. In the literal sense, Old English had ontyndan "kindle, set fire to," from tendan "to kindle" (see tinder). The word was influenced in form, and sometimes in Middle English in sense, by kindel "to give birth" (of animals), "bring forth, produce" (c. 1200), from kindel (n.) "offspring of an animal, young one," from Old English gecynd (see kind (n.)) + -el.

also tinder-box, "box in which tinder and flint are kept," 1520s, from tinder + box (n.); figurative sense of " 'inflammable' person or thing" is attested from 1590s.