xterm serves as a terminal emulator tailored for the X Window System, initially developed to replicate DEC VT102 and Tektronix 4014 hardware while providing a windowed interface for applications that lack direct access to X. Each instance of xterm operates as an independent process, either locally or remotely, with keyboard and mouse inputs being shared, ensuring that only the active window responds to events. It supports ANSI/ISO color through a "new" color model for background erasure and is capable of recognizing the majority of VT220 control sequences, incorporating select features from VT320, VT420, and VT520 devices. Over the years, the terminal description of xterm has transitioned from VT102 (pre-1996) to VT220 (1996–2012), and since 2012, it has adapted to the VT420 standard, thereby maintaining compatibility with contemporary applications. Actively maintained, xterm remains extensible through companion utilities like luit for encoding assistance and the X Toolkit for resource configuration, solidifying its status as a comprehensive and standards-compliant emulator suitable for Unix-based systems. By continuously evolving, xterm ensures it meets the demands of modern users while retaining its historical roots.