Heart-shaped; resembling or having the form of a heart.
From cardio- (Greek kardia, 'heart') + -oid (from Greek eidos, 'form' or 'shape'). The -oid suffix is extremely productive in English, used to create adjectives describing things that resemble something else.
The -oid suffix is everywhere in English—asteroid (star-shaped), spheroid (sphere-shaped), humanoid (human-shaped)—once you recognize it, you unlock thousands of descriptive adjectives about shape and resemblance!
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