[Home](./index.md) > [kibana-plugin-plugins-expressions-server](./kibana-plugin-plugins-expressions-server.md) > [ExpressionFunctionDefinitions](./kibana-plugin-plugins-expressions-server.expressionfunctiondefinitions.md) ## ExpressionFunctionDefinitions interface A mapping of `ExpressionFunctionDefinition`s for functions which the Expressions services provides out-of-the-box. Any new functions registered by the Expressions plugin should have their types added here. Signature: ```typescript export interface ExpressionFunctionDefinitions ``` ## Properties | Property | Type | Description | | --- | --- | --- | | [clog](./kibana-plugin-plugins-expressions-server.expressionfunctiondefinitions.clog.md) | ExpressionFunctionClog | | | [font](./kibana-plugin-plugins-expressions-server.expressionfunctiondefinitions.font.md) | ExpressionFunctionFont | | | [kibana\_context](./kibana-plugin-plugins-expressions-server.expressionfunctiondefinitions.kibana_context.md) | ExpressionFunctionKibanaContext | | | [kibana](./kibana-plugin-plugins-expressions-server.expressionfunctiondefinitions.kibana.md) | ExpressionFunctionKibana | | | [theme](./kibana-plugin-plugins-expressions-server.expressionfunctiondefinitions.theme.md) | ExpressionFunctionTheme | | | [var\_set](./kibana-plugin-plugins-expressions-server.expressionfunctiondefinitions.var_set.md) | ExpressionFunctionVarSet | | | [var](./kibana-plugin-plugins-expressions-server.expressionfunctiondefinitions.var.md) | ExpressionFunctionVar | |