http://wordnik.i2p/words/notation
Various special functions have special abbreviations, as log for logarithm, sin for sine, cos for cosine, tan for tangent, cot for cotangent, sec for secant, cosec for cosecant, vsin for versed sine, sinh for hyperbolic sine, am for amplitude, sn for sine of the amplitude, cn for cosine of the amplitude, etc. (For the special notation of matrices, determinants, graphs, and groups, see those words.)