Substances that burn easily or catch fire easily are called combustible substances. Paper, clothes, wood, LPG are all combustible substances. Without these substances, a fire cannot be started.
Substances which do not burn easily are called non-combustible substances. Glass, stone are all non-combustible substances.
(a) Combustible — charcoal, straw, card board, paper, candle, wood
(b) Non-combustible — chalk, stone, iron rod, copper coin, glass