Tenuis \Ten"u*is\, n.; pl. Tenues. [NL., fr. L. tenuis fine, thin. See Tenuous.]

(Gr. Gram.) One of the three surd mutes [kappa], [pi], [tau]; -- so called in relation to their respective middle letters, or medials, [gamma], [beta], [delta], and their aspirates, [chi], [phi], [theta]. The term is also applied to the corresponding letters and articulate elements in other languages. [1913 Webster]

Source: The Collaborative International Dictionary of English v.0.48
 

Tenuis \Ten"u*is\, n.; pl. Tenues. [NL., fr. L. tenuis fine, thin. See Tenuous.]

(Gr. Gram.) One of the three surd mutes [kappa], [pi], [tau]; -- so called in relation to their respective middle letters, or medials, [gamma], [beta], [delta], and their aspirates, [chi], [phi], [theta]. The term is also applied to the corresponding letters and articulate elements in other languages.

Source: Webster's Revised Unabridged Dictionary (1913)