| J | the 10th letter of the Roman alphabet |
|---|---|
| J | a unit of electrical energy equal to the work done when a current of one ampere passes through a resistance of one ohm for one second |
| J | a neutral meson with a large mass |
| J | United States parapsychologist (1895-1980) |
| J | Scottish geneticist (son of John Haldane) who contributed to the development of population genetics |
| J | Scottish physicist whose equations unified electricity and magnetism and who recognized the electromagnetic nature of light (1831-1879) |
| J | American geneticist who published the complete base sequences for all the genes of a free-living organism, the influenza bacterium |
| J | United States writer (born 1919) |
| J | Confederate general in the American Civil War |
| J | United States lawyer who was director of the FBI for 48 years (1895-1972) |
| J | United States railroad tycoon (1838-1916) |
| J | Scottish dramatist and novelist |