In Australian linguistics, the peripheral consonants are a natural class encompassing consonants articulated at the extremes of the mouth: labials (lip) and velars (soft palate).
That is, they are the non-coronal consonants (palatal, dental, alveolar, and postalveolar).
In Australian languages, these consonants pattern together both phonotactically and acoustically.
In Arabic and Maltese philology, the moon letters transcribe non-coronal consonants, but they do not form a natural class.
In the extinct Martuthunira, the peripheral stops /p/ and /k/ shared similar allophony.