If someone asked you what time it was you would answer, without hesitation, something like 6 o’clock. But why? Why is it “o’clock”, what does that stand for anyway?
Well, “o’clock” stands for “of the clock” and stems back to a much earlier time when clocks weren’t as prevalent. Back as early as the 14th-century people would have answered “6 of the clock” to let people know they were referring to a mechanical clock and not a sundial. In the 18th century slurring of phrases became popular.
Instead of “Will of the Wisp” or Jack of the Lantern” it became “Will-o’-the wisp” and “Jack-o’-lantern”. The same thing happened and it became “6 o’clock”. Although no one has used sundials for years the phrase has just stuck.
- A sundial is a horological device that tells the time of day (referred to as civil time in modern usage) when direct sunlight shines by the apparent position of the Sun in the sky. In the narrowest sense of the word, it consists of a flat plate (the dial) and a gnomon, which casts a shadow onto the dial. As the Sun appears to move through the sky, the shadow aligns with different hour-lines, which are marked on the dial to indicate the time of day. The style is the time-telling edge of the gnomon, though a single point or nodus may be used. The gnomon casts a broad shadow; the shadow of the style shows the time. The gnomon may be a rod, wire, or elaborately decorated metal casting. The style must be parallel to the axis of the Earth’s rotation for the sundial to be accurate throughout the year. The style’s angle from horizontal is equal to the sundial’s geographical latitude. [Back]