1. a substance in gas form, especially water in the form of steam or mist
Usage: British spelling
2. a barely visible or cloudy diffused matter suspended in air
Usage: British spelling

1. to rise or pass off in the form of vapor
Usage: British spelling; intransitive

Examples

• Water vapour rose from the hot pavement after the rain.
• The kettle released clouds of vapour when it boiled.
• Chemical vapours filled the laboratory during the experiment.
• Morning vapour hung low over the lake.
• The liquid began to vapour when heated to high temperatures.
• Petrol vapours are highly flammable and dangerous to inhale.