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sine

(sīn)

n. Abbr. sin

1. The ordinate of the endpoint of an arc of a unit circle centered at the origin of a Cartesian coordinate system, the arc being of length x and measured counterclockwise from the point (1, 0) if x is positive or clockwise if x is negative.

2. In a right triangle, the ratio of the length of the side opposite an acute angle to the length of the hypotenuse.

[Medieval Latin sinus (mistranslation of Arabic jayb, sine, as if jayb, fold in a garment), from Latin, curve, fold.]

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sine

sin θ =

^a/_c

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

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Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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