idio-

American  

1. a combining form meaning “proper to one,” “peculiar,” used in the formation of compound words.

   idiomorphic.

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idio- British  

combining form

1. indicating peculiarity, isolation, or that which pertains to an individual person or thing

   idiolect

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Etymology

Origin of idio-

< Greek, combining form of ídios (one's) own, personal, private, separate, distinct