What does vicinal mean?
Vicinal means neighboring or immediately adjacent. The word can describe places that are close together, as in “vicinal districts,” or more generally things that are closely associated in place or relationship. It is more formal and less common than neighboring, adjacent, or nearby, and is often encountered in technical writing. In chemistry, vicinal describes groups or substituents attached to neighboring atoms, especially neighboring carbon atoms; a vicinal diol, for example, has two hydroxyl groups on adjacent carbons. This specialized meaning reflects the word’s broader sense of things standing side by side. Vicinal comes from Latin vicinalis, a form of vicinus meaning neighboring or adjacent. The same Latin root also underlies words such as vicinity and vicinage. Knowing vicinal is especially useful in chemistry, where it forms a precise contrast with geminal, a term for groups attached to the same atom.
adjectiveNeighboring or immediately adjacent; closely associated in place or relationship. In chemistry, the term describes groups or substituents attached to neighboring atoms.
- Neighboring, adjacent, or closely associated in place.
- Relating to groups or substituents attached to neighboring atoms or carbon atoms.
"The two districts are vicinal, separated only by a narrow park."
"The two districts are vicinal, separated only by a narrow park."
"The molecule contains a vicinal pair of hydroxyl groups on adjacent carbon atoms."
In chemistry, vicinal groups sit next door to one another, unlike geminal groups, which share the same atom.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Words that share this root
Related word forms
How vicinal is actually used
Vicinal is formal and relatively uncommon in everyday speech, where neighboring or adjacent is usually more natural. Its chemistry usage is technical and contrasts with geminal, meaning attached to the same atom.
Easily confused with vicinal
Vicinal means neighboring or adjacent, whereas vicarious means acting on behalf of or through another person.