A single step or stage in the succession of natural descent; a rank or degree in genealogy, the members of a family from the same parents, considered as a single unit.
The average amount of time needed for children to grow up and have children of their own, generally considered to be a period of around thirty years, used as a measure of time.
The formation or production of any geometrical magnitude, as a line, a surface, a solid, by the motion, in accordance with a mathematical law, of a point or a magnitude, by the motion of a point, of a surface by a line, a sphere by a semicircle, etc.