- A loose short-sleeved gown opening in the back, worn by patients undergoing medical treatment or examination.
- A hanger-on about a theater.
- [<em>capitalized</em>] A diminutive of the name <em>John.</em>
- In <em>ichthyology</em>, a cottoid fish, <em>Oligocottus maculosus</em>, with a naked skin, slender head narrowed above, and pointed snout. It is a small species, very abundant along the western coast of the United States.
- Among sailors, a kind of penguin, <em>Pygoscelis tæniata.</em>
- The fish <em>Etheostoma nigrum</em>, a kind of darter.
- A familiar diminutive of <xref urlencoded="john">john</xref>.
- A sculpin.
- a jocose designation of a Frenchman, or of the French people, collectively.
- A <xref>condom</xref>.
- An inexperienced new worker, usually an immigrant.
- A gown with a back opening closed with snaps or ties, worn by hospital patients.
- `Johnny' was applied as a nickname for Confederate soldiers by the Federal soldiers in the American Civil War; `greyback' derived from their grey Confederate uniforms