octad noun. ['ɒktad] M19.
[Greek oktad-, oktas a group of eight, from oktō eight: see -AD¹.]
1. Math.
a. Each of a system of eight numbers analogous to quaternions. Only in M19.
b. Geometry. The set of eight intersections of three quadric surfaces. L19.

2. gen. A group of eight; spec. a unit in the Archimedean system of arithmetical notation representing a power of 10⁸. L19.

3. Chemistry. An octavalent element or group. Now rare or obsolete. L19.

■ oc'tadic adjective L19.

[TahlilGaran] English Dictionary ▲