MemoryInUse[] gives the number of bytes currently being used to store all data in the current Mathematica kernel session. MemoryInUse[$FrontEnd] gives the number of bytes ...
NicholsGridLines is an option to NicholsPlot that specifies contours of constant magnitude and constant phase of the closed-loop system.
NumberFieldClassNumber[\[Theta]] gives the class number for the algebraic number field \[DoubleStruckCapitalQ][\[Theta]] generated by \[Theta].
NumberPadding is an option for NumberForm and related functions which gives strings to use as padding on the left- and right-hand sides of numbers.
OptionInspectorSettings -> {opt_1 -> val_1, opt_2 -> val_2, ...} is a global option that specifies the display of options in the Option Inspector.
Overlaps is an option to StringCases, StringCount, and StringPosition that specifies how to treat overlapping substrings.
PassEventsUp is an option to EventHandler that specifies whether events handled by a particular event handler should be passed up to event handlers in outer expressions.
PlayRange is an option for Play and related functions which specifies what range of sound amplitude levels should be included.
PolynomialGCD[poly_1, poly_2, ...] gives the greatest common divisor of the polynomials poly_i. PolynomialGCD[poly_1, poly_2, ..., Modulus -> p] evaluates the GCD modulo the ...
PrincipalValue is an option for Integrate that specifies whether the Cauchy principal value should be found for a definite integral.