cerran

Old English cerran meant to turn, and the connection to burning is through the transformation fire performs: wood turns black, organic matter turns to carbon, a living thing turns into something inert. Middle English shortened and shifted the word to charren, then char. By the seventeenth century, charcoal was being back-formed as char + coal, though the actual etymology of charcoal is disputed.

Charring is a specific chemical process: pyrolysis, the thermal decomposition of organic material in the absence of oxygen. When wood chars, it does not burn completely—it converts to carbon while retaining its structure. Charcoal, produced by charring wood in sealed kilns, has been essential to metallurgy since the Bronze Age. Without charcoal, you cannot smelt copper. Without smelting copper, you cannot make bronze. Civilization rests on char.

The word entered food vocabulary through cooking. Charring meat, charring peppers, charring bread. Maillard reactions and caramelization at high heat produce the flavors we associate with char: smoky, bitter, complex. Every barbecue and tandoor in the world depends on controlled charring.

British English also uses char as slang for tea, but this is unrelated—it comes from Mandarin chá (茶). The two chars coexist in English without confusion because context is always clear. When a Londoner asks for a cup of char, no one brings them a piece of burnt wood.