Uniaxial
An uniaxial MEMS type piezoelectric accelerometer measures in one direction.
An uniaxial MEMS type piezoelectric accelerometer measures in one direction.
A triaxial MEMS type piezoelectric accelerometer measures in three direction x, y and z.
A 6 degree of freedom MEMS type piezoelectric accelerometer measures six direction - translation along each axis and rotation about each axis