Dynamo node
Short answer
A single function block in a Dynamo graph — the unit you wire together to build an automation.
A Dynamo node is one function in a graph. It has typed inputs on the left, typed outputs on the right, and performs one operation: pick elements, get a parameter, compute a value, draw geometry. Nodes come from Dynamo's core library, from Revit's API wrappers, or from community packages installed via the Dynamo Package Manager (popular ones include Clockwork, archi-lab, Rhythm). Custom nodes are saved as .dyf files and shared with a team.