The phrase "core part" refers to an essential or central component of something. It is the most important part that cannot be removed or changed without significantly altering the entire thing. Full definition
The other core part of the school's philosophy is an extensive, well - utilized peer mediation program. (educationworld.com)
One core part of their framework tracks employee performance in real - time. (entrepreneur.com)
Paying sufficient attention to management issues such as innovation, strategy, cost control and staff engagement is also critical and I think these topics should be viewed as core parts of the role, rather than as «optional extras» in the management of a legal department. (lawyer-monthly.com)