D defs.my
Entry 2 senses Webster, 1913

Nisus

· Ni·sus · IPA
01 n. A striving; an effort; a conatus.
  1. 1.
    A striving; an effort; a conatus.
    “A nisus or energizing towards a presented object.” — Hickok.
  2. 2.
    The periodic procreative desire manifested in the spring by birds, etc.(Physiol.)