That would be a pedometer.
The word is "pedometer." A pedometer is a device that measures the distance a person walks by counting the steps taken.
foot
That is not a word, but pedometer is an instrument that measures how far a person has walked, or are you thinking of podiatry?
A measuring wheel, string or measuring tape. A laser is also used to measure distances to as far away as the moon.
The word for how far something travels is distance.
There is no instrument as far as I know
The distance
The speed of a wave is measured by calculating the distance a wave travels per unit time. It is usually expressed in meters per second (m/s) or other similar units depending on the type of wave being measured.
The speed of a wave is how far the wave travels in one unit of time.
Light travels an infinite distance until it is absorbed by an object.
Your answer depends on where you start.
Far, our, the, his, her,