Definitions for "Pi bond"
a bond that has an electron distribution above and below the bond axis
A bond formed by the edge-on overlap of p atomic orbitals.
( bond) Compare with sigma bond. In the valence bond theory, a pi bond is a valence bond formed by side-by-side overlap of p orbitals on two bonded atoms. In most multiple bonds, the first bond is a sigma bond and all of the others are pi bonds.