A unit of length (or distance) in US units equal to 12 inches.
The abbreviation is: ft
Or sometimes the single quote mark: '
Example: 10 feet can be written as 10 ft, or just 10'
A foot is exactly 0.3048 meters in the Metric System (the foot is defined that way).
Example: This ruler (not to scale) measures 12 inches which equals 1 foot, and is equal to 0.3048 m or 30.48 cm in the Metric System
See: Inch