Following down the left side column we have inverse, square, cube, sine (sign), and log. Right side's a little more complicated.
The first one is "real" - when applied to a complex number - that is, one with real and imaginary (designated by some factor times "i") parts - you take the real component only and drop the imaginary component. i.e. You drop the i's (eyes). "Imag" (imaginary) is the converse of "real", so that would be only the i's.
The inverted triangle is a math operator called "grad", and it takes the gradient of a function. When applied to a vector - and we know it's a vector because of the cross product operator - it's known as the "curl".
Then finally, we have "root".