# Glossary

## flow

In Node-RED, a flow is a connected subgraph of nodes with its own data sources and data sinks. Flows may be interconnected via indirect links.

## node

Nodes are the core elements in Node-RED. Nodes function as black boxes, that take in data as messages. These messages are transformed by the node and output again.

## Node-RED

Node-RED is a flow-based programming tool for transferring and manipulating data from devices, APIs or online services. With Node-RED, a program is represented as a directed graph. The nodes represent transformations. The connections represent the data flow.

## Secure copy protocol (SCP)

The secure copy protocol enables secure transmission of computer files between a local host and a remote host or between two remote hosts.