The Collaborative International Dictionary of English v.0.48:

Tinder \Tin"der\, n. [OE. tinder, tunder, AS. tynder, tyndre;
   akin to tendan to kindle, D. tonder tinder, G. zunder, OHG.
   zuntara, zuntra, Icel. tundr, Sw. tunder, Dan. t["o]nder. See
   Tind.]
   Something very inflammable, used for kindling fire from a
   spark, as scorched linen.
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   German tinder. Same as Amadou.

   Tinder box, a box in which tinder is kept.
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