what does the 2 in E=MC2 stand for?

E = M C ²
E = M x C ² (C is squared)

It is the "squared" referring to the constant "c", meaning it is the speed of light times itself.

"Squared" = ^2

You're funny... you have really pieced this together!

E = m c^2
the 2 is square
or
E = m x c x c
= mcc

the 2 means that C is SQUARED,
which means power of 2
which means C is multiplied by another C

In expanded form, E = M times C times C

e = mc^2

2 = to the power of 2