(1) What does a barometer measure?
Answer: Atmospheric pressure.
(2) What does a piezometer measure?
Answer: Groundwater pressure.
(3) What does a hygrometer measure?
Answer: Air humidity.
(4) What does a micrometer measure?
Answer: The size of very small objects.
(5) What does an inclinometer measure? (bonus: what does a clinometer measure).
Answer: The angle of tilt or elevation, as compared to the direction of gravity (bonus: the same as an inclinometer).