Wikipedia
Aterm
"aterm" can also refer to a software library intended for the manipulation of trees of terms.1
aterm is the AfterStep terminal emulator for the X Window System. Based on rxvt 2.4.8 (in 1999), aterm is a color VT100 terminal emulator that supports basic pseudo-transparency.
As of January 1, 2008 aterm is no longer maintained; its developers stated that they would concentrate their efforts on urxvt