the world > matter > gas > becoming or making into gas > become gas [verb (intransitive)] > become vapour (12)
intransitive. To become vapour; to pass off or become dissipated in vapour. Also †to evaporate to.
To pass or be dissolved into a state of vapour or moisture. rare.
intransitive. To evaporate.
intransitive. To become vaporous.
= evaporate, v. 1. literal and figurative.