1. (

• kernel ,
• substance ,
• core ,
• center ,
• centre ,
• essence ,
• gist ,
• heart ,
• heart_and_soul ,
• inwardness ,
• marrow ,
• meat ,
• nub ,
• pith ,
• sum ,
• nitty-gritty

) the 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" ;