This is the 396th most frequent French word.
principal
Main; chief; primary.
Here, 'principal' is used as an adjective to mean 'main' or 'primary' to describe the goal.
Le principal objectif de cette réunion est de discuter du projet.
The main goal of this meeting is to discuss the project.
Here, 'principal' acts as a noun meaning 'the head of an institution,' specifically a school principal.
Le principal de l'école a annoncé une nouvelle politique.
The principal of the school announced a new policy.
In this example, 'principal' agrees in gender with the noun 'raison' and describes it as the key or primary reason.