[noun] [U] - small pieces of something dry that burns easily and which can be used for lighting firesWe used some dry grass and dead twigs as tinder to light the camp fire.The grass is tinder-dry (= so dry that it will burn easily), so there's a risk of fire.
TINDER
Meaning of TINDER in English
Cambridge English vocab. Кембриджский английский словарь. 2012