Open English Wordnet
Nouns
(n)kernel, substance, core, center, centre, essence, gist, heart, heart and soul, inwardness, marrow, meat, nub, pith, sum, nitty-grittythe choicest or most essential or most vital part of some idea or experience“the gist of the prosecutor's argument”, “the heart and soul of the Republican Party”, “the nub of the story”
(n)center, centre, center of attention, centre of attentionthe object upon which interest and attention focuses“his stories made him the center of the party”
(n)center, centre, nerve center, nerve centrea cluster of nerve cells governing a specific bodily process“in most people the speech center is in the left hemisphere”
(n)center field, centerfield, center, centrethe piece of ground in the outfield directly ahead of the catcher“he hit the ball to deep center”
(n)plaza, mall, center, shopping mall, shopping center, shopping centre, centremercantile establishment consisting of a carefully landscaped complex of shops representing leading merchandisers; usually includes restaurants and a convenient parking area; a modern version of the traditional marketplace“a good plaza should have a movie house”, “they spent their weekends at the local malls”
Verbs
(v)focus on, center on, revolve around, revolve about, concentrate on, center, centrecenter upon“Her entire attention centered on her children”, “Our day revolved around our work”