Phonet. articulated with little muscle tension and little or no aspiration, as (b) and (d)
Origin of lenisL, smooth, soft, mild: see lenient
a lenis sound
Articulated with relatively low pressure of the airstream below the glottis, as English (b) and (d) compared with (p) and (t).
Origin of lenisLatin lēnis soft ; see lē- in Indo-European roots.
Latin lenis (“soft, smooth").