lusus naturae (n.)

1610s, "pertaining to play or sport" (a sense now obsolete), from Latin ludicrus "sportive" (source of Old French ludicre), from ludicrum "amusement, game, toy, source of amusement, joke," from ludere "to play."

This verb, along with Latin ludus "a game, play," is from the PIE root *leid- or *loid- "to play," perhaps literally "to let go frequently" [de Vaan], which is the source also of Middle Irish laidid "impels;" Greek lindesthai "to contend," lizei "plays;" Albanian lind "gives birth," lindet "is born;" Old Lithuanian leidmi "I let," Lithuanian leisti "to let," laidyti "to throw," Latvian laist "let, publish, set in motion."

Sense of "ridiculous, apt to evoke ridicule or jest" is attested from 1782. Related: Ludicrously; ludicrousness.

late 13c., "restorative powers of the body, bodily processes; powers of growth;" from Old French nature "nature, being, principle of life; character, essence," from Latin natura "course of things; natural character, constitution, quality; the universe," literally "birth," from natus "born," past participle of nasci "to be born," from PIE root *gene- "give birth, beget."

By mid-14c. as "the forces or processes of the material world; that which produces living things and maintains order." From late 14c. as "creation, the universe;" also "heredity, birth, hereditary circumstance; essential qualities, inherent constitution, innate disposition" (as in human nature); also "nature personified, Mother Nature." Nature and nurture have been paired and contrasted since Shakespeare's "Tempest."

The phrase "nature and nurture" is a convenient jingle of words, for it separates under two distinct heads the innumerable elements of which personality is composed. Nature is all that a man brings with himself into the world; nurture is every influence from without that affects him after his birth. [Francis Galton, "English Men of Science: Their Nature and Nurture," 1875]

Specifically as "the material world beyond human civilization or society; an original, wild, undomesticated condition" from 1660s, especially in state of nature "the condition of man before organized society." Nature-worship "religion which deifies the phenomena of physical nature" is by 1840.

Nature should be avoided in such vague expressions as 'a lover of nature,' 'poems about nature.' Unless more specific statements follow, the reader cannot tell whether the poems have to do with natural scenery, rural life, the sunset, the untouched wilderness, or the habits of squirrels. [Strunk & White, "The Elements of Style," 3rd ed., 1979]

Man, her last work, who seem'd so fair,

Such splendid purpose in his eyes,

Who roll'd the psalm to wintry skies,

Who built him fanes of fruitless prayer,

Who trusted God was love indeed

And love Creation's final law—

Tho' Nature, red in tooth and claw

With ravine, shriek'd against his creed—

[Tennyson, from "In Memoriam"]