Hours
Minutes
Seconds
Meter. . . . . Length Kilogram . . . Mass Second. . . . Time
there is only one
Fahrenheit, Celsius and Kelvin
Meters, liters, kilograms.
seconds
nanoseconds
In itself it is none of them - it is just a number.However if some units are attached, it can be any of them:If its units are a linear measure, eg 472 m, it is a lengthIf its units are a square measure, eg 472 sq cm, it is an areaIf its units are a weight measure, eg 472 kg, it is massIf its units are a time measure, eg 472 seconds, it is timeIf its units are a temperature measure, eg 472 K, it is temperature.
-- the Astronomical Unit -- the Light Year -- the Parsec -- the Magnitude
Milligrams, grams or kilograms are three examples.
You can't convert that. You can only convert units that measure the same type of thing - for example, units of length to units of length, units of mass to units of mass, units of time to units of time, etc.
Three quarter note beats are in each measure in 3/4 time.
However you want: Speed is a measure of units of distance per units of time. Miles per hour or meters per second are common ones.