LineIndentMaxFraction is an option for Cell, StyleBox, and Style that specifies the maximum fraction of the total page width to indent at the beginnings of lines.
LinkProtocol is an option to LinkLaunch, Install, and related functions that specifies the underlying data transport protocol to use for a new MathLink link.
LocatorRegion is an option for Locator that specifies where the locator object should by default be allowed to go when it is dragged.
MatchLocalNames is an option for Trace and related functions that specifies whether symbols such as x should match symbols with local names of the form x$nnn.
Medium
(Built-in Mathematica Symbol) Medium is a style or option setting that specifies that objects should be medium sized.
NotebooksMenu is a global option that specifies which recently opened notebooks are listed under the File menu.
OperatingSystem is an option for file and related operations that specifies the type of operating system to use to determine file name and other conventions.
PageFooters is an option for notebooks that specifies what should be inserted as the footer of each page of a notebook when it is printed.
PageHeaders is an option for notebooks that specifies what should be inserted as the header of each page of a notebook when it is printed.
PrintPrecision is an option for selections that specifies the maximum number of digits used for displaying a machine-precision number.