1. A collection of four things having something in common. 2. In chemistry, a quadrivalent element. 3. In heredity, a bivalent chromosome which divides into four in the maturation division.
The number of four; a collection of four things.
An element with a valence or combining power of four.
A group of four similar bodies.
An element having a valency of four; a quadrivalent element.
A group of four micrococci.