Terminals

Terminals are end points or interfaces where systems meet users or other components. The term spans several domains, including computing, transportation, and biology, each with its own typical meaning.

In computing, a terminal originally referred to a device that provided input and output to a central computer, often consisting of a keyboard and screen connected by a network. Early terminals were “dumb,” offering little processing power and relying on a host system. Modern use favors terminal emulators—software programs that imitate traditional terminals within graphical operating systems—allowing direct access to command shells, scripting, and remote sessions. Common protocols for remote terminal access include SSH and Telnet, though SSH is preferred for secure communication. Terminal environments are central to system administration and software development, with many variants such as xterm, GNOME Terminal, and iTerm2 supporting multiple tabs and customization.

In transportation, a terminal is a facility at ports, airports, or transit hubs where passengers or goods begin or end journeys. Terminals group processing areas like check-in counters, security, baggage handling, gates or platforms, and often customs and immigration. At large airports or seaports, multiple terminals may serve different airlines or regions, with transfer connections consolidated within a terminal complex or linked by transit routes.

In biology, the term terminal refers to the end of a structure. In neuroscience, the axon terminal (or nerve terminal) is the distal end of a neuron where neurotransmitters are released at synapses, enabling communication with other neurons or muscles.

Across domains, terminals share the core idea of being endpoints or interfaces that enable interaction, transfer, or signaling between systems.