Help with definition PLEASE

I’ve been around here for a while but never understood what is meant by a “portable” app.
Sorry for such a silly question.
Answer #1
http://en.wikipedia.org/wiki/Portable_application
Answer #2
It can be argued that most “portable applications”, especially those that are available here aren’t really portable.
A truly portable application will run off any storage medium without the need for installation, and will not leave any traces on the host computer. Basically a self-contained application.
Answer #3
A portable app for me is one i’m able to use without admin rights, as they’re the only ones i can use. Some have their own registry entries within the programs, while others may say it’s not possible to write to it, but they still work. They are also easier to delete without the hassle and properly installed program can have.
Answer #4
A portable app for me is one i'm able to use without admin rights, as they're the only ones i can use. Some have their own registry entries within the programs, while others may say it's not possible to write to it, but they still work. They are also easier to delete without the hassle and properly installed program can have.
It’d perfectly possible to write to a virtual registry – that’s how Thinstall works.
The virtual reg files are in a sub folder called “skel” something..
Portables do sometimes fail with device drivers that are needed as part of the program.