ColumnsEqual is an option for the low-level function GridBox which specifies whether all columns in the grid should be assigned equal width.
CreateIntermediateDirectories is an option for CreateDirectory and related functions that specifies whether to create intermediate directories in a directory path specified.
DefaultMenuStyle is a low-level option for menu-generating constructs that specifies the default style to use for displaying menu items.
DeleteDirectory["dir"] deletes the specified directory.
DeleteFile["file"] deletes a file. DeleteFile[{"file_1", "file_2", ...}] deletes a list of files.
DifferentialRootReduce[expr, x] attempts to reduce expr to a single DifferentialRoot object as a function of x.DifferentialRootReduce[expr, {x, x_0}] takes the initial ...
DragAndDrop is a global front end option that specifies whether to allow drag-and-drop editing.
EdgeRules[g] gives the list of edge rules for the graph g.
ExcludePods is an option to WolframAlpha that specifies pod IDs to exclude from the results.
GridDefaultElement is an option for the low-level function GridBox that specifies what to insert when a new element is created interactively in a GridBox.