minor groove

This term is a specialized anatomical descriptor used exclusively in molecular biology and biochemistry. It refers to the specific spatial geometry of the DNA double helix, where the sugar-phosphate backbones are closer together than in the major groove. This structural feature is critical for the binding of specific proteins and small molecules that recognize the chemical signatures of the base pairs without needing to unwind the helix.

Because it describes a specific structural component of a biological molecule, it is used in a highly technical register. It is almost never found in general conversation and appears primarily in peer-reviewed scientific literature, textbooks, and laboratory reports.