dz

dz is a two-letter sequence with multiple, independent meanings across language, technology, and mathematics. It is the ISO 639-1 code for Dzongkha, the official language of Bhutan. Dzongkha is written in the Tibetan script and is spoken by a substantial portion of the Bhutanese population. In Internet infrastructure, the country code top-level domain .dz is assigned to Algeria and is used for domain names associated with the country.

dz is used as a digraph in several languages to represent a voiced alveolar affricate. It is most commonly associated with Polish, where it denotes the sound /d͡z/, as in dziewięć. In other languages, 'dz' may appear as a sequence of two letters rather than a single phoneme, depending on the orthographic system.

In mathematics and science, 'dz' is also used as the differential of a variable z, denoting an infinitesimal change. It appears in integrals, differential equations, and changes of variables. The meaning is context-dependent and does not correspond to a fixed symbol beyond these conventional uses.