Tenuis

A tenuis consonant (pronounced /ˈtɛnjuːɪs/ or, to distinguish it from tenuous, /ˈtɛnuːɪs/), plural tenues (/ˈtɛn(j)uːiːz/), is a consonant that is not voiced, aspirated or glottalized – that is, a 'plain' obstruent such as [p, t, k, s, ǁ] with a voice-onset time approximating zero. The term comes from the Classical tradition, where it indicates the voiceless, unaspirated series of Greek plosives, π τ κ. It may be useful where terms such as 'voiceless', 'unaspirated' or 'plain' are ambiguous. An obsolete synonym is surd.