Definition of cores:
(n) :
In general usage, an essential part of a thing surrounded by other essential things.
(n) :
The central part of a fruit, containing the kernels or seeds.
(n) :
The heart or inner part of a physical thing.
(n) :
The anatomical core, muscles which bridge abdomen and thorax.
(n) :
The center or inner part of a space or area.
(n) :
The most important part of a thing or aggregate of things wherever located and whether of any determinate location at all; the essence.