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Before clocks were commonplace, the terms 'sunwise' and 'deasil' or 'deosil' (from the Scottish Gaelic deiseil, from the same root as the Latin dexter, "right") were used for clockwise. (Of course, deasil (righthandwards) is only sunwise in the Northern Hemisphere.) 'Withershins' or 'widdershins' (from Middle Low German weddersinnes, "opposite course") was used for counterclockwise.
Technically, the terms clockwise and counterclockwise can only be applied to a rotational motion once a side of the rotational plane is specified, from which the rotation is observed. For example, the daily rotation of the Earth is counterclockwise when viewed from the North Pole, and clockwise when viewed from the South Pole.
Clocks traditionally follow this sense of rotation because of the clock's predecessor: the sundial. Clocks were first built in the Northern Hemisphere, and they were made to work like sundials. In order for the sundial to work (in the north), it must be placed looking southward. Then, when the Sun moves in the sky (east to south to west), the shadow cast by the sundial moves in the opposite direction, that is west to north to east. That's why hours were drawn in sundials in that manner, and that's why modern clocks have their numbers set in the same way.
Occasionally, clocks whose hands revolve counterclockwise are nowadays sold as a novelty. Historically, some Jewish clocks were built that way, for example in some Synagogue towers in Europe. This was done in accordance with the right-to-left reading direction of Hebrew.
Typically, screws and bolts are loosened counterclockwise and tightened clockwise. One mnemonicA mnemonic ( SAMPA /n@'mAnIk/ in US or /n@'mQnIk/ in UK) is a memory aid. Mnemonics are often verbal, are sometimes in verse form, and are often used to remember lists. Mnemonics rely not only on repetition to remember facts, but also on creating associat for remembering this is "righty-tighty, lefty-loosey" (right to tighten, left to loosen.)
In trigonometryTrigonometry (Greek: "the measure of triangles") is a branch of mathematics dealing with angles, triangles and trigonometric functions such as sine and cosine . It has some relationship to geometry, though there is disagreement on exactly what that relati, and mathematicsMathematics is commonly defined as the study of patterns of structure, change, and space; more informally, one might say it is the study of "figures and numbers". In the formalist view, it is the investigation of axiomatically defined abstract structures in general, plane angleThis article is about angles in geometry. For other articles, see Angle (disambiguation An angle (from the Lat. angulus a corner, a diminutive, of which the primitive form, angus does not occur in Latin; cognate are the Lat. angere, to compress into a bens are conventionally measured counterclockwise.
Clockwise and counterclockwise distinctions occur throughout nature: see