Interpunct

The interpunct, also called the middle dot, is a punctuation mark consisting of a small dot centered on the baseline. It has a typographic history as a sign used to separate elements within writing, and it remains in use in several language traditions and technical contexts.

Historically, the term derives from Latin meaning “to place between.” In medieval and early modern manuscripts, a dot placed between words helped indicate separation when spaces were not consistently used. Over time, its role in everyday prose diminished in many languages, but it persisted in specialized conventions and forms. In Unicode, the standard middle dot is encoded as U+00B7, and a separate Katakana middle dot used in Japanese is found as U+30FB.

Contemporary usage varies by language and field. In Japanese typography, the nakaguro (中黒) is widely used to separate foreign loanwords, names, and compounds written in katakana or mixed scripts, as well as to organize items in lists. In linguistics and phonetics, the interpunct marks morpheme or syllable boundaries in transcriptions and dictionaries. In mathematics and computing, the middle dot serves as a multiplication sign or a dot product, and sometimes as a delimiter in data formats or programming languages.

Thus, the interpunct is a versatile typographic symbol with historical roots and modern applications that differ across contexts, from language practice to mathematical notation.