There are three types of moduli
(a) the Young Modulus - tensile and compression longitudinal stress
(b) the shear modulus - a shearing stress
(c) the bulk modulus - volume changes of the specimen
The Young Modulus

This is defined as the ratio of longitudinal stress to longitudinal strain.
This is the modulus we need if we want to investigate the change of length of a object, or more accurately any of its linear dimensions (width, length or height).