What does levorotatory mean?
Levorotatory is a technical adjective describing optical activity: the rotation of the plane of polarized light to the left, or counterclockwise, when viewed in the direction of light propagation. Chemists use it to characterize certain substances, molecules, or solutions, often through measurements made with a polarimeter. The word is part of a paired system with dextrorotatory, which describes the opposite direction of rotation. Levorotatory does not generally mean that an object visibly turns left; its meaning is specifically tied to polarized light. The term is especially associated with the study of molecular structure and stereochemistry, where opposite forms of a molecule may rotate polarized light in different directions. It is most appropriate in formal scientific writing rather than everyday speech.
adjectiveLevorotatory means rotating the plane of polarized light to the left, or counterclockwise, when viewed in the direction of the light's propagation. The term is used chiefly in chemistry and optics to describe substances or solutions with this optical activity.
- Rotating the plane of polarized light to the left or counterclockwise, especially when viewed in the direction of propagation.
"The chemist carefully measured the levorotatory behavior of the solution using a polarimeter."
"The compound was identified as a levorotatory substance in the laboratory."
"A levorotatory sample produces a characteristic change in the plane of polarized light."
Mirror-image molecules can behave like optical twins: one may be levorotatory, turning polarized light left, while its counterpart turns it right.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does levorotatory come from?
The word combines the combining form levo-, meaning “left,” with rotatory, meaning “turning” or “rotating.” Both elements reflect the compound's literal sense of turning to the left. The related noun levorotation names the optical rotation itself. The terminology developed within the scientific vocabulary of optics and chemistry, where the distinction between left- and right-rotating behavior is important.
Related word forms
How levorotatory is actually used
This is a specialized scientific term, used mainly in chemistry, optics, and related technical contexts. It should not be confused with a simple statement that an object turns leftward.
Easily confused with levorotatory
Levorotatory rotates polarized light to the left, whereas dextrorotatory rotates it to the right.
Levorotatory is the standard scientific spelling; levorotary is an uncommon variant.