GrayLevel[level] is a graphics directive that specifies the gray-level intensity with which objects that follow should be displayed. GrayLevel[g, a] specifies opacity a.
InexactNumberQ[expr] returns True if expr is an inexact real or complex number, and returns False otherwise.
IsotopeData[{Z, A}, " property"] gives the value of the specified property for the isotope with atomic number Z and mass number A.IsotopeData["name", " property"] gives the ...
ItemAspectRatio is an option for GraphicsGrid which specifies the ratio of height to width for the regions in which items are placed in the graphics grid.
JacobiSymbol[n, m] gives the Jacobi symbol (n/m).
JoinForm[type] is a graphics directive that specifies what type of joins should be used to connect segments of lines, tubes, edges, and related primitives.
Larger
(Built-in Mathematica Symbol) Larger is a style or option setting that specifies that objects should be larger.
LayerSizeFunction is an option for TreePlot that gives a function to specify the relative height to allow for each layer.
LegendAppearance is an option for charting functions that specifies the appearance of any legends that are generated.
LineSpacing is an option for Style and Cell that specifies the spacing between successive lines of text.