Definition - A sound made by raising the lower lip towards the upper front teeth, e.g. the [v] in varicose.

Etymology -
The word derives from the Latin labium, lip.

Oxford English Dictionary -
Its first citation is from 1669:
"P. and B. are Labial: Ph. and Bh. are *Labio-dental."
(Holder Elem. Speech 71)

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