lenis

[lee-nis, ley-] /ˈli nɪs, ˈleɪ-/
adjective
1.
pronounced with relatively weak muscular tension and breath pressure, resulting in weak sound effect: in stressed or unstressed position, (b, d, g, j, v, th̸, z, and zh) are lenis in English, as compared with (p, t, k, ch, f, th, s, and sh), which are fortis.
Compare fortis (def 1).
noun, plural lenes
[lee-neez, ley-] /ˈli niz, ˈleɪ-/ (Show IPA)
2.
a lenis consonant.
Origin
1925-30; < Latin: soft, mild, gentle
British Dictionary definitions for lenis

lenis

/ˈliːnɪs/
adjective
1.
(of a consonant) articulated with weak muscular tension
noun (pl) lenes (ˈliːniːz)
2.
a consonant, such as English b or v, pronounced with weak muscular force
Compare fortis
Word Origin
C19: from Latin: gentle