means To set something on fire, or to spark a sudden burst of energy, passion, or action.

from From Latin 'ignire,' meaning 'to set on fire,' built on 'ignis' — fire itself — which is also the root of 'igneous' rocks born in volcanic heat. That same 'ignis' is possibly a distant cousin of words for fire in other Indo-European tongues, including the Sanskrit 'agni.' English borrowed it relatively late, in the 17th century, when 'ignite' arrived to do the heavy lifting that 'kindle' and 'inflame' had managed before.