center field; center of attention; center on; centerfield; centre; centre of attention; concentrate; concentrate on; core; essence; eye; focus; focus on; gist; halfway; heart; heart and soul; inwardness; kernel; mall; marrow; meat; middle; midpoint; midway; nerve center; nerve centre; nitty-gritty; nub; pith; plaza; pore; revolve about; revolve around; rivet; shopping center; shopping centre; shopping mall; snapper; substance; sum;