pipeline elevation

This would generally be the elevation, in millimeters, relative to a known site elevation of zero.

Try this,
BOP = Bottom Of Pipe

CL = Center Line

Hedpe,

This applies to yourself and any other junior/trainee pipers.

Find a senior piper in you place of work, and ask them to act as your mentor, ask questions, and write down the answers.

Also, take the time to go through the training articles on this site, also look through the tips section, and the tools section.

There is loads of very good information there if you look hard enough!

Finally, if you're looking for any more abbreviations, such as BOP, CL etc, go to www.pipingdesigners.com/Tools.htm#gen and look at the piping glossary therein.

Hope this helps,
Anton