One click further give you the definations.

SEd being a Stream editor-- used for editing streams of text on the fly..
Auk is programing lanuage -- but as faldage points out, this is all Unix stuff..

as a language, Unix is not so much user unfriendly, as just, damn particular with who it make friends with... at least according to the Unix nerds i know.

http://www.oreilly.com/catalog/sed2/desc.html