Sin is the short version of the trigonometry SINE() function. This short version is always used in equations and expressions since it takes less space. Used in an equation it might look like

sin x = 0.22
This would be interpreted as "The sine of x is 0.22". Most mathematicians would speak it as "sine x equals 0.22". (It is never pronounced 'sin'.)

Pages referring to 'sin'

Interactive demonstration of the graph of the sine function in trigonometry
Where sine waves occur in nature - sound waves, mechanical motion, electronics, radio waves
Definition of the sine function as applied to right triangles in trigonometry
Definition of the arcsin function in trigonometry. The inverse of the sine function. The angle whose sine is a given number.
A brief introduction to trigonometry to allow geometry formulas to be calculated. How to claculate sin, cos, tan functions.