- E1(also e)noun (plural Es or E's)1》 the fifth letter of the alphabet.2》 denoting the fifth in a set.3》 Music the third note of the diatonic scale of C major.————————E2abbreviation1》 East or Eastern.2》 informal the drug Ecstasy or a tablet of Ecstasy.3》 denoting products, in particular food additives, which comply with EU regulations. See also E-number.4》 exa- (1018).5》 Spain (international vehicle registration). [from Sp. España.]symbol Physics1》 electric field strength.2》 energy.
English new terms dictionary. 2014.