# Definition of cardioid in US English:

## cardioid

### noun

Mathematics
• 1A heart-shaped curve traced by a point on the circumference of a circle as it rolls around another identical circle.

• ‘For the special case of b = a, the result is a two-dimensional heart-shaped curve known as the cardioid.’
• ‘There are exactly three parallel tangents to the cardioid with any given gradient.’
• ‘The caustic of a circle with radiant point on the circumference is a cardioid, while if the rays are parallel then the caustic is a nephroid.’
• ‘M is the point of the moving circle that traces the cardioid.’
• ‘If the focus of the parabola is taken as the centre of inversion, the parabola inverts to a cardioid.’
1. 1.1 A directional microphone with a pattern of sensitivity of this shape.
• ‘For the upright, I used two mics: one cardioid large-diaphragm near the floor, pointing up at the bridge, and the xt up closer to the players' right hand to capture more of the string noise and attack.’
• ‘The DPA 4015's wide pattern provides a welcome intermediate alternative to omnis and so-called first-order cardioids.’
• ‘DPA calls this mic a wide cardioid, and, indeed, between 500 Hz and 10k Hz, the 4015's polar response begins to resemble an omni mic.’
• ‘The wide cardioid does make them more sensitive to what's going on off-axis, so be mindful of things like nearby walls when you're positioning them.’
• ‘These microphones are invariably cardioid microphones, meaning that the shape of the sound sensitive field around the mike is in the shape of a heart, essentially picking up sound in both forward and side directions.’
• ‘Because the rear lobes of these hypercardioids tend to ‘cross’ the channels of the front stereophonic image, a ‘purist’ might prefer to use cardioids.’
• ‘MG recommends its low-noise M930s, but it works fine with any studio cardioids.’
• ‘We had Sennheiser MKH20s as the flanking mics and more Sennheiser MKH Series mics used in the surround pickup; then across the front of the chorus was the B&K DPA 4023 miniature cardioids.’

• Of the shape of a cardioid.

• ‘A similar procedure can be used for the intersection points on the cardioid shape and the outer green fringes.’
• ‘His first two papers are on the cardioid curve which he named.’

### Origin

Mid 18th century: from Greek kardioeidēs ‘heart-shaped’, from kardia ‘heart’ + eidos ‘form’.

## cardioid

/ˈkärdēˌoid//ˈkɑrdiˌɔɪd/