each other, one another Two people look at each other. More than two look at one another. Either phrase may be used when the number is indefinite: we help each other; we help one another.

eco- In general, no hyphen when used as a prefix relating to ecology or the environment: ecosystem, ecotourism. See Words Formed With Prefixes under General Style Preferences.

economic, economical Economic means “of or relating to large-scale finances”: federal economic policy. Economical means “thrifty; financially efficient”: an economical purchase.

e.g. See i.e.

eleventh Spell out only in the phrase the eleventh hour, meaning at the last moment; otherwise, use the numeral without superscript: 11th.

email No hyphen (AP style); but hyphenate other forms: e-book, e-business, e-commerce, e-reader.

ensure, insure, assure Use ensure to mean “guarantee an event or condition”: use these guidelines to ensure consistency in your writing. Use assure to mean “to inform confidently with a view to removing doubt or anxiety”: students were assured that housing would be available. Use insure only when referring to financial insurance: the policy insures his life.

entitled, titled Use entitled to mean “a right to do or have”: He was entitled to a raise. Use titled when referring to the title of a paper, book, etc.: He is presenting a paper titled “Jane Jacobs on Economic Development” at the spring conference. To be more concise, eliminate the word titled by recasting the sentence: He is presenting a paper, “Jane Jacobs on Economic Development,” at the spring conference.

envelop (v.), envelope (n.)

equal, equaled, equaling When using equal as an adjective, it is without comparative forms: a more equitable distribution of wealth, not a more equal distribution of wealth.

equally as Do not use these words together (one is sufficient): She and Jane were equally wise; or She was as wise as Jane.

equitable See equal above.

ESP Acceptable in second references for extrasensory perception.

et al. This is the abbreviated form of et alii (“and others”)—the others being people, not things. Because al. is an abbreviation, the period is required.

etc. This is the abbreviated form of the Latin et cetera (“and other things”), which implies a list of things too extensive to recite. It should never be used in reference to people.

EU No periods. Acceptable in second references for European Union.

euro, eurodollar, eurozone Lowercase, no hyphens.

ex- In general, no hyphen when using this prefix in the sense of “out of”: excommunicate, expropriate. Hyphenate when using ex- in the sense of “former”: ex-convict, ex-president. When referring to a specific person, former is usually better: former Gov. Mario Cuomo. See Words Formed with Prefixes under General Style Preferences.

extra- In general, no hyphen when using this prefix in the sense of “outside of” unless it is followed by a word beginning with the letter a or by a capitalized word: extralegal, extramarital, extraterrestrial; but extra-alimentary, extra-Britannic. Hyphenate when using extra- as part of a compound modifier describing a condition beyond the usual size, extent, or degree: extra-large book, extra-mild weather, extra-dry conditions. See Words Formed with Prefixes under General Style Preferences.

extracurricular No hyphen.

executor Lowercase; use for both men and women.