The grapheme D (minuscule: d) is a letter in the Czech and Slovak alphabets. It is formed from Latin D with the addition of hácek and is placed right after regular D in the alphabet. It is used to denote , the voiced palatal plosive. It was also used in Polabian.

The +D (or Plus D) was a floppy disk and printer interface for the Sinclair ZX Spectrum home computer, developed as a successor to Miles Gordon Technology's earlier product, the DISCiPLE. It was designed to be smaller, cheaper, simpler and thus more reliable.

D (named dee ) is the fourth letter in the basic modern Latin alphabet. It is used to denote 500 in Roman numerals

D is the fourth letter of the Latin alphabet. It can also refer to the following:

• D, denoting the Federal Reserve Bank of Cleveland in the serial numbers of United States dollars
• D, Mitsubishi Electric's mobile phones in Japan
• D, the New York Stock Exchange ticker symbol for Dominion
• D: All Things Digital, an annual technology conference sponsored by the Wall Street Journal, produced and hosted by columnist Walter Mossberg

D* (pronounced "D star") is any one of the following three related incremental search algorithms:

• The original D*, by Anthony Stentz, is an informed incremental search algorithm.
• Focused D* is an informed incremental heuristic search algorithm by Anthony Stentz that combines ideas of A* and the original D*. Focused D* resulted from a further development of the original D*.
• D* Lite is an incremental heuristic search algorithm by Sven Koenig and Maxim Likhachev that builds on LPA*, an incremental heuristic search algorithm that combines ideas of A* and Dynamic SWSF-FP.

D+ can refer to:

• D+ (band), indie rock band based in Anacortes, Washington
• Digital+, former name of Canal+ (Spanish satellite broadcasting company)
• D+, a grade (education)

D- means:

1. Placed before a U.S. state, usually in parentheses, indicates the person it applies to is a Democratic Party politician of that state. "R-" is used for the Republican Party.
2. An academic grade given by certain institutions. Slightly better than an F and slightly worse than a D. See Grade (education).
3. A prefix signifying chirality of a molecule

Damnation (from Latin ) is the concept of everlasting divine punishment and/or disgrace, especially the punishment for sin as threatened by God (e.g. ). A damned being "in damnation" is said to be either in Hell, or living in a state wherein they are divorced from Heaven and/or in a state of disgrace from God's favor. Those Christians in purgatory, the "Church Suffering", are not considered damned, because their stay there is not eternal, while people who are damned to Hell will stay there eternally.

Delta (uppercase Δ, lowercase δ; Délta; Modern Greek ) is the fourth letter of the Greek alphabet. In the system of Greek numerals it has a value of 4. It was derived from the Phoenician letter Dalet . Letters that come from delta include Latin D and Cyrillic Д.

Detlef Soost (born July 2, 1970 in Berlin-Pankow, East Germany), also using the name D! (formerly Dee!), most often called Detlef D! Soost, is a German dancer and choreographer.

Don (, , ) from Latin dominus, is an honorific title used in Iberia and Italy. The female equivalent is Doña , Donna , and Dona , abbreviated "Dª" or simply "D."

The Swiss Federal Institute of Technology Zurich or ETH Zürich (ETHZ) is an engineering, science, technology, mathematics and management university in the City of Zurich, Switzerland. Like its sister institution École Polytechnique Fédérale de Lausanne (EPFL), it is an integral part of the ETH Domain that is directly subordinate to Switzerland's Federal Department of Home Affairs.

An emoticon is a pictorial representation of a facial expression using punctuation marks and letters, usually written to express a person's mood. Emoticons are often used to alert a responder to the tenor or temper of a statement, and can change and improve interpretation of plain text; emoticons for a smiley face :-) and sad face :-( appear in the first documented use in digital form. The word is a portmanteau word of the English words emotion and icon. In web forums,  instant messengers and online games, text emoticons are often automatically replaced with small corresponding images, which came to be called emoticons as well. Certain complex character combinations can only be accomplished in a double-byte language, giving rise to especially complex forms, sometimes known by their romanized Japanese name of kaomoji.

In telecommunication, an end-of-transmission character (EOT) is a transmission control character. Its intended use is to indicate the conclusion of a transmission that may have included one or more texts and any associated message headings.

Eth (Ð, ð; also spelled edh or eð) is a letter used in Old English, Icelandic, Faroese (in which it is called edd), and Elfdalian. It was also used in Scandinavia during the Middle Ages, but was subsequently replaced with dh and later d. Its use has survived in Iceland. The capital eth resembles a D with a line through the vertical stroke. The lower case resembles an insular d with a line through the top. The lower-case letter has been adopted to represent a voiced dental fricative in the IPA.