Kernels
(Built-in Mathematica Symbol) Kernels[] gives the list of running kernels available for parallel computing.
Log2
(Built-in Mathematica Symbol) Log2[x] gives the base-2 logarithm of x.
MantissaExponent[x] gives a list containing the mantissa and exponent of a number x. MantissaExponent[x, b] gives the base-b mantissa and exponent of x.
MaxIterations is an option that specifies the maximum number of iterations that should be tried in various built-in functions and algorithms.
Parallelization is an option for Compile that specifies whether it should create a compiled function that could run in parallel.
RoundingRadius is an option for Rectangle, Framed, and related functions that specifies the radius of the circle to use in rendering rounded corners.
SphericalHarmonicY[l, m, \[Theta], \[Phi]] gives the spherical harmonic Y_l^m(\[Theta], \[Phi]).
WaveletScale is an option for ContinuousWaveletTransform and related constructs used to specify the smallest resolvable scale.
$MaxExtraPrecision gives the maximum number of extra digits of precision to be used in functions such as N.
$MinPrecision gives the minimum number of digits of precision to be allowed in arbitrary-precision numbers.