nisus

noun ! Definition from Wiktionary (CC BY-SA). Pronunciation from Wiktionary, via Kaikki.org. More about nisus at Wordnik → Where our words come from →

1. A mental or physical effort to attain a specific goal; a striving.
2. The periodic procreative desire manifested in the spring by birds, etc.
3. The contraction of the diaphragm and abdominal muscles to evacuate faeces or urine.