MaxRecursion is an option for functions like NIntegrate and Plot that specifies how many recursive subdivisions can be made.
MemberQ
(Built-in Mathematica Symbol) MemberQ[list, form] returns True if an element of list matches form, and False otherwise. MemberQ[list, form, levelspec] tests all parts of list specified by levelspec.
MonomialList[poly] gives the list of all monomials in the polynomial poly.MonomialList[poly, {x_1, x_2, ...}] gives the list of monomials with respect to the variables x_i in ...
NHoldAll is an attribute which specifies that none of the arguments to a function should be affected by N.
NHoldRest is an attribute which specifies that all but the first argument to a function should not be affected by N.
ParagraphSpacing is an option for Cell, StyleBox, and Style that specifies how much extra space to leave between successive paragraphs of text.
PlotMarkers is an option for graphics functions like ListPlot and ListLinePlot that specifies what markers to draw at the points plotted.
PopupWindow[expr, contents] displays as expr, but pops up a window containing contents when clicked.
Rescale
(Built-in Mathematica Symbol) Rescale[x, {min, max}] gives x rescaled to run from 0 to 1 over the range min to max. Rescale[x, {min, max}, {x_min, x_max}] gives x rescaled to run from x_min to x_max over ...
Round
(Built-in Mathematica Symbol) Round[x] gives the integer closest to x. Round[x, a] rounds to the nearest multiple of a.