"Vertical Growng" and " Main-lining" What do these terms mean?

Hello
Over the last few weeks I have learned a vast amount about growing.
Two terms that I often see in posts are "Vertical growing" and "Main lining".

Could someone please explain to me what these things actually are?

Many thanks.

Google is your friend.

Google "vertical growing cannabis" and "mainlining cannabis" and the world is your destiny to explore.....

But why bother having a forum full of experts but resorting to Google?

And Google isn't my friend.
Google is a tax avoiding, corporate monster that I'd rather not associate with.

I can say one good thing about them.
They don't make cunts out of themselves with infantile attempts at humour that come over as smart assed and infantile.

So thanks.
You made me realize that even Google isn't all bad.

If you don't want to use google browse through the site. It won't be hard to find vertical growing and main lining if you try to look for it.