L-(Laevus, Left)
Definition: A stereochemical prefix denoting configuration opposite to that of D-glyceraldehyde, based on the Fischer projection.
Context: Indicates mirror-image relationship to D-forms; unrelated to optical rotation (d/l).
Example: L-alanine corresponds to the configuration of L-glyceraldehyde.
Related Terms: D-; Fischer Projection; Absolute Configuration.
Reference: Fischer (1891).
Levo- (l, –)
Definition: Denotes a compound that rotates plane-polarized light to the left (counter-clockwise).
Context: Paired with dextro-; unrelated to R/S assignment.
Example: L-(–)-lactic acid.
Related Terms: Dextro-, Optical Activity, Specific Rotation.
Reference: IUPAC Gold Book.