noun, plural: hearts
(1) (anatomy) The chambered muscular organ of vertebrates that moves blood through the body by repeated, rhythmic contractions.
(2) The analogous contractile structure in invertebrates, such as annelids, mollusks, and arthropods.
(3) (botany) The core of a plant, fruit, vegetable, etc.; the solid central part without sap or albumen.
(2) That which resembles a heart in shape, i.e. a roundish figure with an obtuse point at one end and an indentation at the other end.
(3) A position relating to the mid or center, or that which is the most essential or vital part.
In mammals and birds, the heart consists of four chambers: right and left ventricles, and right and left atria. In reptiles and amphibians, the heart has only three chambers. In fish, the heart is composed of one auricle and one ventricle.
Word origin: Middle English hert, from Old English heorte.