Which of the following is not a unit used to measure pressure?
a. torr
b. newton
c. atmosphere
d. millimeter of mercury

The answer is Newton.

Explanation:

In order to determine the unit that it is not used to measure pressure, we have to define the units for every option and then compare them.

Torr (symbol: Torr): is a unit of pressure based on an absolute scale, now defined as exactly 1/760 of a standard atmosphere (≈ 133.32 Pa).

Newton (symbol: N) is the International System of Units (SI) derived unit of force.

Atmosphere (symbol: atm): the standard atmosphere is a unit of pressure defined as 101325 Pa (1.013 bar)

Milimeter of mercury (symbol: mmHg): is a manometric unit of pressure, formerly defined as the extra pressure generated by a column of mercury one millimetre high, and currently defined as exactly 133.32 Pa.

Therefore, the physics unit that not represent a pressure measure is Newton.