Noun

(en noun)

The process of inhaling and exhaling; breathing, breath.

An act of breathing; a breath.

* 1931 , William Faulkner, Sanctuary , Vintage 1993, p. 76:

Gowan snored, each respiration choking to a huddle fall, as though he would never breathe again.

Any similar process in an organism that lacks lungs that exchanges gases with its environment.

The process by which cells obtain chemical energy by the consumption of oxygen and the release of carbon dioxide.

Noun

The act of reproducing new individuals biologically.

* {{quote-magazine, year=2013, month=May-June, author= Katrina G. Claw

, title= Rapid Evolution in Eggs and Sperm , volume=101, issue=3, magazine=(American Scientist) , passage=Many genes with reproductive roles also have antibacterial and immune functions, which indicate that the threat of microbial attack on the sperm or egg may be a major influence on rapid evolution during reproduction .}}

The act of making copies.

A copy of something, as in a piece of art; a duplicate.