| an extraordinary or unusual thing, person, or event; an exceptional example or instance. |
| a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison. |
"If I coveted nowe to avenge the injuries that you have done me, I myght laughe in my slyve." [John Daus, "Sleidanes Commentaries," 1560]The noun is first attested 1680s, from the verb. Meaning "a cause of laughter" is from 1895; ironic use (e.g. that's a laugh) attested from 1930. Nitrous oxide has been called laughing gas since 1842 (for its exhilarating effects). Laugh track "canned laughter on a TV program" is from 1966.
laugh at
Treat lightly, scoff at. For example, He said the other children all laughed at his jacket, or They stopped laughing at his theory when it proved to be correct. [Late 1300s]