Achiral: An object that is not chiral.
Chiral: An object that is not superposable with its mirror image.
Constitutional isomer: One of a set of isomers that differs in the sequence of attachment or bonding of the atoms.
Dextrorotatory: Rotation of plane polarized light in a clockwise direction.
Diastereomer: One of a set of stereoisomers that are not enantiomers.
Enantiomer: One of a pair of stereoisomers that are nonsuperposable mirror images.
Isomer: One of a set of compounds with identical molecular formulas.
Levorotatory: Rotation of plane polarized light in a counterclockwise direction.
Meso compound: A compound that has at least two stereocenters but is achiral.
Optically active: Rotation of plane polarized light.
Plane polarized light: Light in which the electric field component oscillates in a single plane.
Polarimeter: A device to measure rotation of plane polarized light.
Racemic mixture: An equimolar mixture of a pair of mutual enantiomers.
Resolution: Separation of mutual enantiomers.
Specific rotation: The magnitude of rotation of plane polarized light of compound in a 10.0 cm path length, and at concentration of 1.00g/mL or neat if the compound is a liquid.
Stereocenter: An atom that has four different groups attached
to it. (Not limited to just carbon.)
Stereoisomer: One of a set of isomers that have the same
connectivity
of atoms, but differ in the position of the atoms in space.
Stereoisomers cannot be interconverted by rotation around a single
bond. (Conformational isomers are not stereoisomers.)