| an extraordinary or unusual thing, person, or event; an exceptional example or instance. |
| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |
Haldane Hal·dane (hôl'dān', -dən)
Family of Scottish intellectuals and scientists, including John Scott Haldane (1860-1936), a physiologist noted for his studies of the exchange of gases during respiration; and his son John Burdon Sanderson Haldane (1892-1964), a geneticist.