data Originally this word was a plural of datum. As a plural noun, the word data normally takes plural verbs and pronouns: The data have been carefully collected. But as a collective noun, it may take a singular verb or pronoun: The data is sound (in this context, data is a single unit). In formal writing (and always in the sciences), use data as a plural.

data processing (n. and adj.) Two words, no hyphen.

day care Two words, no hyphen, in all uses.

Dean’s List Capitalize when referring to a specific list at the college: Students in the BA and BS programs who achieve 3.5 GPAs are awarded the honor of Dean’s List, which is recorded on the students’ transcripts. (This is an exception to AP style, which is lowercase in all instances.)

decision making, decision maker (n.), decision-making (adj.)

definite, definitive Definite means “clear, exact”: a definite yes. Definitive means “conclusive, final, most authoritative”: the definitive version.

determine whether, determine if The first phrasing is irreproachable style; the second is acceptable in less formal writing. The same is true of decide whether versus decide if. Also see whether.

dialogue, dialog Use dialogue when referring to a conversation, discussion, the conversational element of literary or dramatic composition, etc. Use dialog only when referring to a window on a computer screen that is used for choosing options or entering data: a dialog box.

different from, than The phrase different from is generally preferable to different than (this design scheme is different from that one), but sometimes the adverbial phrase differently than is all but required: she described the scene differently than he did. There are rare cases where different than is appropriate, if than operates as a conjunction: Development is different in New York than in Los Angeles.

dilemma This word means more than a problem; it implies a choice between two unattractive alternatives: The country’s authorities faced a dilemma: respect the constitutional deadline and organize botched elections, or ignore that deadline and slide into a situation of unconstitutional power.

dis- In general, no hyphen after this prefix: disallow, disapprove, disbelieve, discomfort. See Words Formed With Prefixes under General Style Preferences.

disburse, disperse To disburse is to distribute money. To disperse can be to distribute other things or to break up, as an unruly crowd.

discriminating (adj.), discriminatory The word discrimination can be used in either a negative or a positive sense, and these adjectives reflect that ambivalence. Discriminatory means “reflecting a biased treatment”: discriminatory employment policy. Discriminating means “analytical, discerning, tasteful”: a discriminating palate.

disinterested, uninterested Disinterested means “impartial, not having a financial or personal interest at stake.” Avoid it as a replacement for uninterested, which means “lacking interest, unconcerned, bored.”

dissociate (v.) Not disassociate; the word means to “to separate from association or union with another”: The author has tried to dissociate herself from her earlier works.

DNS Abbreviation for Domain Name System, an international network of internet domain servers, names, and addresses. Spell out on first reference.

download No hyphen.

drunk, drunken (adj.) Drunk is used after a form of the verb to be: He was drunk. Drunken is used before nouns: a drunken driver, drunken driving.

DSL Acceptable in all references for digital subscriber line.

due to the fact that Use because instead.

DVD Acceptable in all references for digital video disc.

DVR Acceptable in all references for digital video recorder.

Updated May 3, 2016