The first gear of an transmission, which provides the lowest output speed and greatest mechanical advantage.

A violinist who is assigned to play melody (usually more technically difficult music).

The leading woman in a specified field of endeavor. / Alternative spelling of First Lady

A member of an emergency service who is first on the scene, or among those first on the scene, at an emergency. / A member of an emergency service trained to provide emergency medical care.

(mathematics, logic) Of one of a series of models, languages, relationship, forms of logical discourse, etc., being the simplest one or the first in a sequence. / Of fundamental importance.

The wife of the chief executive of a nation; especially the wife of the President of a country; or a woman (e.g. a relative) who takes on similar public duties, as when the chief executive is unmarried.

Happening for the first time; doing something for the first time.

(astronomy) The waxing lunar phase, from new moon to half way between new moon and full moon.

The highest quality of gemstones, especially of diamonds and pearls. / (by extension) The highest rank or quality or the greatest degree.

Alternative spelling of firststringer