dm

Dm is an abbreviation that can denote several unrelated terms across different fields. The meaning is typically inferred from context, since capitalization and disciplinary conventions vary.

In music, Dm most commonly denotes the D minor chord or the D minor key. As a chord, Dm consists of the notes D, F, and A. The key of D minor is the relative minor of F major and typically features one flat (B-flat) in its key signature.

In measurement and science, dm stands for decimeter, an SI unit equal to one-tenth of a meter. It is used for practical measurements, especially in contexts where metric prefixes offer convenient scaling, though the meter remains the primary SI base unit for precision work.

In computing, dm is short for device-mapper, a Linux kernel framework that provides a generic layer for logical volume management and disk encryption (for example, dm-crypt). The term appears in utilities such as dmsetup and in related documentation.

In biology and genetics, Dm can be used as a shorthand for Drosophila melanogaster in some literature, a widely used model organism in genetic and developmental studies.

In astronomy and astrophysics, DM (often written as DM) stands for dispersion measure, the integrated electron density along the line of sight to a pulsar or fast radio burst. DM is expressed in parsecs per cubic centimeter (pc cm^-3). A related use of DM is as an acronym for dark matter, though that usage is typically capitalized (DM) and context-dependent.

Other uses may exist in specialized domains, but the above represent the most commonly encountered meanings of Dm.