It would depend on what type of frequency you are measuring.
One instrument in electric and electronic engineering would be an oscilloscope.
In the E-M spectrum, it is called a frequency meter.
Measuring cylinder
measuring cylinder
You adjust the measuring instrument :)
When are air velocity measurement used
In the E-M spectrum, it is called a frequency meter.
Force meter is the instrument used in measuring force.
Measuring cylinder
A protractor is used for drawing and measuring angles.
Frequency counter
measuring cylinder
Photometer
A clock
A protractor
A scale
Weighing scales
A thermometer