The phrase "major constituent" refers to a significant or important part of something. It indicates that this particular element plays a crucial role or has a significant influence on the overall entity. Full definition
Empowered by law, the board is required to represent major constituent groups. (educationnext.org)
Gaining adequate knowledge of becoming a good medical assistant contains one more major constituent known as a «Practical» training. (medicalassistanttrainings.com)
China already has more than 20 local trading platforms that allow industrial firms to buy and sell permits for pollutants like sulphur dioxide and nitrogen oxides, major constituents of smog and acid rain. (scientificamerican.com)