tynder

Old English tynder meant dry material used to catch a spark and start a fire. The word derives from Proto-Germanic tundrą, to kindle or ignite, and is related to Old Norse tundr and Old High German zuntara. Before matches existed—and they did not exist until 1826—every fire in Europe started with flint struck against steel, sending sparks into tinder. The tinder box was as essential as a knife.

Tinder had to be prepared carefully. Charred linen (char cloth), dried fungus (amadou), birch bark, and shredded cedar bark all served as tinder across different cultures and periods. The quality of your tinder could mean the difference between a warm supper and a cold night. Frontiersmen, soldiers, and householders all kept tinder boxes within reach.

The friction match, invented by John Walker in 1826, made tinder obsolete in a single generation. By 1850, tinder boxes were curiosities. The word survived only in the metaphorical sense: a tinderbox situation, dry as tinder, a spark in a tinderbox. All described situations primed for rapid, explosive change—places where a small provocation could start a conflagration.

In 2012, Sean Rad and Justin Mateen launched Tinder, the dating app. The name was deliberate: the app was designed to create sparks between people. Swipe right and the match might catch. The oldest fire-starting word in the English language was repurposed for the oldest fire-starting activity in human nature.