Stereoisomer: Molecules that have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in space.
Enantiomer: A type of stereoisomer that is a non-superimposable mirror image of another molecule, having exactly opposite configurations at all chiral centers.
Chiral Center: A carbon atom that has four different groups attached to it, giving rise to non-superimposable mirror image molecules