The primary function refers to the main or most important purpose or role of a particular organ or system.
Related terms
Secondary function: Refers to additional roles or purposes that an organ or system may have apart from its primary function.
Tertiary function: Relates to even further roles or purposes that an organ or system may serve, usually less significant than both primary and secondary functions.
Vital function: Describes critical functions that are necessary for survival and proper functioning of an organism.