главным образом

см. тж. в основном; в первую очередь

The attachment consists essentially (or chiefly, or mainly, or in the main) of a cable drum and ...

The shield has been designed for the most part from common materials.

The greater (or major) part of our work was carried out indoors.

The foam consists predominantly of closed cells.

This element is composed principally (or chiefly, or mainly, or primarily) of Zircaloy-2.

This compound is presently used primarily as ...

Источник: Русско-английский научно-технический словарь на Gufo.me