The phrase "is mainly defined by" is correct and usable in written English.
You can use it when describing the factors that cause something to be what it is. For example: "The success of a business is mainly defined by its access to capital, its customer base, and its ability to innovate."
The Warsaw music scene is mainly defined by its club culture.
The flat white economy is driven by online retail and marketing but it comprises many different businesses: McWilliams argues that it is mainly defined by the types of people it employs.
It seems the Chinese government learned that international responsibility is mainly defined by political responses to international crises, especially security issues, rather than simply economic aid to poor countries.
The MMS-OMP algorithm is mainly defined by (19) and (20).
The interconnection scheme is mainly defined by the connectivity (describes which neurons are connected) and the types of connections.
And the ellipticity of the elliptical DHBs is mainly defined by the focal length of the cylindrical lens and the Fresnel number of the optical system.
It is shown that the characteristic temperatures for the motional regime transitions are mainly defined by the asphaltenes' content.
The representativeness of these measures strongly depends on the quality of inferred model parameters, which are mainly defined by the parameters of the variogram or the covariance function.
A straightforward mechanical processing protocol for raw bamboo, which leads to a fibrous material with physical features that are mainly defined by the bamboo species, has been developed.
The number of robotic arms, the number of joints of each arm, and the torque level that each joint motor should supply are mainly defined by the grasping phase and the de-orbit phase.
The properties of the polymers, which are mainly defined by the nature and composition of the integrated monomers, differ significantly leading to remarkable changes in the linear range of detection and maximum current of the derived amperometric glucose biosensors.
