ClearAll[symb_1, symb_2, ...] clears all values, definitions, attributes, messages, and defaults associated with symbols. ClearAll["form_1 ", "form_2", ...] clears all ...

Clock[] represents a clock variable whose value cycles continuously from 0 to 1 once per second when it appears inside a dynamically updated object such as a Dynamic. ...

Context[] gives the current context. Context[symbol] gives the context in which a symbol appears.

Contexts[] gives a list of all contexts. Contexts["string"] gives a list of the contexts that match the string.

ContextToFileName["context"] gives the string specifying the file name that is by convention associated with a particular context.

ControllerInformation[] gives dynamically updated information on currently connected controller devices.

DefaultNotebook is a global option that specifies which notebook is used as a template for all new notebooks.

DialogProlog is an option for Dialog that can give an expression to evaluate before the dialog starts.

DirectedGraphQ[g] yields True if the graph g is a directed graph and False otherwise.

DistributedContexts is an option for various parallel computing functions that specifies which definitions for symbols appearing in an expression should be distributed to all ...