Isoclines

Part of speech: noun

Definitions

1. A set of lines on a map or graph that connect points with equal values of a particular variable, often used in geographical studies
2. Lines drawn on a chart to represent locations where a specific phenomenon shares the same level or quality, useful in scientific analyses
3. Graphical representations that depict areas with uniform values of a variable, commonly employed in fields like geography and meteorology

Etymology: "Isoclines" is the plural of "isocline," a term built from two Greek-derived pieces. The first, "iso-," comes from the Greek "isos," meaning "equal," and appears in many scientific coinages where sameness of some quantity is the point, as in "isotherm" and "isobar." The second, "-cline," comes from the Greek "klinein," meaning "to lean" or "to slope," the same root that gives "incline" and "decline." Put together, the word describes a line along which something stays equal while the ground or surface tilts. On a map, an isocline joins places that share the same slope, the same steepness of gradient. Geologists also use the term for lines of equal dip in layered rock, where the tilt of strata is measured. The word is a technical coinage from classical roots rather than an ancient term, so its scientific sense is modern, even though each of its parts is centuries older.