`Nobody," according to George Bernard Shaw in Major Barbara, can say a word against Greek, "it stamps a man at once as an educated gentleman."
Perhaps this is why meteorologists like to mystify their laity with seasonings of prefixes and suffixes pilfered from that ancient language. An- and kat- meaning "up" and "down" respectively, will serve as an example.
These prefixes are used, for instance, to classify isallobars. The word isallobar comes from the Greek, being a loose amalgam of isos meaning "equal" or "the same", allos meaning "other", and baros the word for "weight" which we now associate with pressure. An isallobar is a line drawn on a weather map to indicate equal changes in atmospheric pressure in a given period.
One could be drawn, for example, to join a series of points where the pressure fell by one hectopascal in the preceding six hours; another could then be drawn to show where the pressure dropped by two hecto pascals in the same period; and so on until the line joining points where the fall was five hectopascals might be a closed loop, identifying clearly the zone where the fall of pressure in the recent past was greatest.
Meteorologists identify two kinds of isallobars: anallobars and katallobars. Anallobars, as the prefix suggests, are lines depicting rising or positive changes in pressure and are drawn on the weather chart as dashed blue lines; katallobars are lines depicting falling or negative pressure tendencies and are depicted by dashed red lines. The zero pressure tendency isallobar is drawn in purple.
Their usefulness lies in the fact that they indicate clearly the direction in which the various pressure systems have been moving, and consequently provide a strong hint as to their likely future progress. Typically, katallobars precede depressions while anallobars precede anticyclones; lows normally move in the direction of maximum pressure falls and highs in the direction where the pressure rises have been greatest.
The speed of both features as they migrate, usually eastwards, across the weather chart is closely related to the "isallobaric gradient", the extent to which the anallobars or katallobars are very close together or are widely spaced.
So, as a 19th century clergyman, the Rev Thomas Gais ford, put it in his sermon one Christmas Day in the cathedral at Oxford: "Nor can I do better, in conclusion, than impress upon you the study of Greek literature, which not only elevates above the vulgar herd but leads, not infrequently, to positions of considerable emolument."