**Sca**, through,, u rpov, measure), in geometry, a line passing through the centre of a circle or conic section and terminated by the curve; the "principal diameters of the ellipse and hyperbola coincide with the "axes" and are at right angles; " conjugate diameters " are such that each bisects chords parallel to the other.

Sometimes diagrams (**Sca-**ypa4al or i) roypa4a1) are mentioned, and sometimes given (e.g.

**Sca** y ., 1890, 25.

The latter has no allusion to the KaXov g pyov, the ErepoScSaaxaXEav, the **Sca**/3E13atouaOat, &c., of the others, and contains one or two specific phrases of its own.