cardioid

 
Pronunciation: /ˈkɑːdɪɔɪd/

noun

Mathematics
  • a heart-shaped curve traced by a point on the circumference of a circle as it rolls around another identical circle.
  • (also cardioid microphone) a directional microphone with a heart-shaped pattern of sensitivity.

adjective

  • of the shape of a cardioid.

Origin:

mid 18th century: from Greek kardioeidēs 'heart-shaped', from kardia 'heart' + eidos 'form'