Word Perfect is a multi-platform word processor. Its been around a while.
Version history Edit
WordPerfect 4.2 for AS/400 exists.
This appears to be the last version released for the Amiga. Also on VAX\VMS there was a release of version 5.1.
This is the last release for Unix. 
There appears to be a release of Word Perfect v 4.1.12, 4.1, and 5.0 for Amiga.  The last Amiga version is 5.0.
Versions 4.0 through 8.0 exist on Unix. There is a Linux version of 8.0 as well.
WordPerfect 4.2 was released for NextStep.