%tenuis%

‖n.; pl. Tenues [ NL., fr. L. tenuis fine, thin. See Tenuous. ] (Gr. Gram.) One of the three surd mutes κ, π, τ; -- so called in relation to their respective middle letters, or medials, γ, β, δ, and their aspirates, χ, φ, θ. The term is also applied to the corresponding letters and articulate elements in other languages. [ 1913 Webster ]