ORGAN [C] › the organ inside your chest that sends blood around your body: Isabel's heart was beating fast. heart disease/failure CENTRE [no plural] › the centre of something: Her office is in the heart of Tokyo. the heart of sth › the most important part of something: We need to get to the heart of the matter.
FEELINGS [C, U] › someone's deepest feelings and true character: She has a kind heart. SHAPE [C] › a shape that is used to mean love hearts › playing cards with red, heart shapes on them
at heart › used to say what someone is really like: I'm just a kid at heart.
in your heart › used to say what you really think: In his heart he felt they were wrong.
with all your heart › used to say that you feel something very strongly: I thank you with all my heart.
not have the heart to do sth › to decide not to do something that would make someone unhappy
learn/know, etc sth by heart › to be able to remember all of something
→ See also a change of heart