General LSX Automobile Discussion - What is LSX?

I have always thought LSX just stood for all LS engines. But today a friend made me doubt that I knew what it is. So to the question what does LSX really stand for?

LSX is a GMPP aftermarket crate engine.

LSx is a generic term for any small block chevy engine in the Gen III-IV series.

Lsx blocks are slightly differnt than a ls block the lsx gmpp blocks are nicer imo.

Lsx blocks are slightly differnt than a ls block the lsx gmpp blocks are nicer imo.

Not really an opinion truff.

The GM Performance Parts LSX block is better than a factory block. Its rated at what 2500hp? Its sleeves won't crack, and it has provisions for 6 Bolt Heads.

Thanks