- See Punctuation.
- Data is singular when it is used as a collective noun that represents a unit. This data is not logical.
- Data is plural when it refers to individual items: The data are in line with the previous research.
- Use datum in reference to a single bit of information.
data center, data processing (n. and adj.)
- Use the sequence of month, day and then year, placing a comma after the day of the month: School starts on September 2, 2012.
- If the day of the month is not provided, do not use commas: He received the award in December 2004.
- Days of the week should precede the date and should be followed by a comma: He died on Tuesday, October 10, 2000.
- Avoid superscript constructions such as January 15th. Write as January 15. Use superscript constructions only in reference to centuries: He lived in the 19th century.
- Also see months.
- Two words, no hyphen, in all uses.
day to day, day-to-day
- Hyphenate when used as a compound modifier: They have extended the contract on a day-to-day basis.
daylight saving time
- Not savings. No hyphen.
days of the week
- Do not abbreviate days of the week in running text.
- In tabular format where space is limited, abbreviate the days as follows, without periods: Sun, Mon, Tue, Wed, Thu, Fri, Sat.
- Capitalize when used as a formal title before a name: Dean Sherif Kamel; otherwise, lowercase.
- Lowercase in all uses
- Add the letter s with no apostrophe: the 1990s, or use an apostrophe and write as: the ’90s. The important thing is to be consistent.
- Always precede decades with the word the.
- Two words, no hyphen. But hyphenate when used as a compound modifier: decision-making process.
- See academic degrees.
degrees with distinction
- Lowercase cum laude (honors), magna cum laude (high honors), summa cum laude (highest honors). Do not italicize.
- Lowercase: She served as a delegate at the Model United Nations.
- Click here for a list of academic departments.
- Hyphenate: dean-designate. Capitalize only the first word if used as a formal title before a name.
- Not dialog (also dialoguing, dialogued).
- Use figures and spell out centimeters, meters, inches, feet, yards to indicate height, length and width: 6 centimeters, 1 meter, 4 yards.
- Always use figures and hyphenate adjectival forms before nouns: He climbed the 4-meter long ladder.
- You have a diploma in (not of) a certain field: diploma in teaching. Use of if it is part of the official name: Diploma of Higher Education.
- Lowercase when referring to a compass direction: Take the highway north.
- Capitalize when referring to specific regions: the Far East, the North Coast, the Midwest, the Western Hemisphere or names of countries: Northern Ireland, South Korea.
- Lowercase when directions describe a section of a state or country: western Texas, southern California.
- Disinterested means impartial, neutral, not taking sides: disinterested party in the dispute; disinterested referee. Uninterested means that someone lacks interest: He was uninterested in the subject.
- Use disc to refer to phonograph records, disc jockey and laser-based devices (laserdisc, videodisc, and a blu-ray disc), as well as for disc brake.
- Use disk to refer to the hard disk on which computer data can be stored and for medical references, such as a slipped disk.
- Dispersion of people away from their homeland. Lowercase.
distinguished visiting professors
- Capitalize when preceding a name: Distinguished Visiting Professor Maria Menocaul spoke about the art and architecture of Medieval Spain.
- Lowercase when it comes after the name: Maria Menocaul, distinguished visiting professor of Spanish and Portuguese at Yale University, gave a lecture yesterday.
- Also lowercase when not associated with a name: He is a distinguished visiting professor of chemistry.
- Use DVP on second reference.
do's and don'ts
doctoral, doctorate, PhD
- Doctoral is used as an adjective: He is a doctoral candidate at the University of California, Santa Barbara. He entered the doctoral program last year.
- Doctorate or PhD is the degree that someone earns: She earned her doctorate after five years of hard work.
- Capitalize honorary degrees: honorary Doctorate of Science, honorary Doctorate of Humane Letters. See honorary degrees.
- Put the $ sign before the figure, leaving no space: He earns $50 per week. Do not use $ before the amount and the word dollars after it.
- Spell out as dollars lowercase when no figure is given: I lent her a dollar. His bank account is in dollars.
- When the figure is in millions, spell out the word million and use numerals up to two decimal places: He won $5.75 million.
- For specified amounts, the word takes a singular verb: The ransom they requested was $250,000.
door to door, door-to-door
- Hyphenate when used as a compound modifier: He is a door-to-door salesman. But: He went from door to door.
- Use for medical doctors or dentists, not people with doctorate degrees.
- Capitalize and use before the name: Dr. Magdi Yacoub performed sensitive heart surgery.
- Capitalize Zamalek Dormitory, as it is the official name. Use hostel on second reference.
- Could also refer to it as the dormitory, the AUC hostel or the Zamalek residence.
- Avoid dorm (casual reference).
- The rules for prefixes apply, but in general, no hyphen. Some examples: downgrade, downtown, download.
- Do not capitalize. Separate with a slash, not a hyphen.
- Do not use add/drop.
drop out (v.), dropout (n.)
- Abbreviation on first reference for digital video disc (or digital versatile disc).
- Acceptable on second reference for digital video recorder.