Definition - A type of consonant in which the air escapes through a narrow gap between lips, teeth, and tongue, for example, the [f] in fine, the [s] in sign, and the [v] in vine.

1. [f] is a voiceless, labiodental fricative, [v] is a voiced, labiodental fricative, [s] is a voiceless, alveolar fricative, and [z] is a voiced, alveolar fricative.

Etymology -
The term derives from the Latin fricare, to rub.

Oxford English Dictionary -
Its first citation is from 1863:
"H belongs, therefore, to the unvocalised strong fricatives."
(Lepsius Standard Alphabet 68)

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