expression
mostly involve; principally involve
Used in the pattern 〜を主とする to indicate that something mainly consists of or is centered around a particular element. Often found in formal or written descriptions.
See also: 主として (しゅとして)
この地域の産業は農業を主としている。
The industry in this region mostly involves agriculture.
彼の研究は中世史を主としている。
His research principally involves medieval history.