Earth—Always written up, except when referring to soil. Sun is also always up, but moon may be written down. [revised 08/2001]
Earth system—open as both noun and adjective. [09/2000]
ed.—abbreviation for edition; used in reference and publication lists. Edition numbers are treated according to the usual rule for numbers: first ed., 12th ed.
Ed.—abbreviation for editor; used in reference and publication lists
editorial notes—In all publications, these are styled in italics with no indent. At end; use —Ed. (that's an em dash).
e.g.—not in italics; always set off by commas; stands for "exempli gratia" (for example)
Ekman-Hartmann boundary layers
email—no longer written with a hyphen [revised 03/2011]
elements—See "chemical elements."
El Niño—with tilde. Often El Niño/Southern Oscillation.
emission-line profile—Use hyphen.
Employee Activities Committee—abbreviated EAC
England—rather than United Kingdom; see also exceptions at "United Kingdom."
English institutions—use their spelling (e.g., "Centre")
enstrophy—mean square vorticity
equations—It's up to the author whether to number equations or not. Abbreviate in-text citations except at the beginning of a sentence. For example:
But we find (Eq. 5) that . . .
In Eqs. 23 and 25 we find . . .
From Eqs. 4–7 we derive that . . .
Equation 17.1 provides that . . .
Always include Eq. or Equation with the number. [revised 02/2000]
Ethernet—communications network (trademark of Xerox)
Eulerian—initial cap (measures parcels of air passing over a point; cf. "Lagrangian")
exhibit titles—use title caps and italics, Wave Tank, Thunderstorm Detectives. [ASTC style, 02/2000]