Tera Term is a terminal emulator (communications) program. It emulates different types of terminals, from DEC VT100 to DEC VT382. It supports telnet, SSH 1 & 2, serial port connections, IPv6 acccess and UTF-8. It also has a built in Macro scripting language and a few other useful plugins.
DWT is a simple, no-frills terminal emulator based on the VTE widget, whose main feature is being feature-less, thus simple, lean, mean and a very good companion for tiling window managers like DWM (or my own XDWM fork).