E12 or E-12 may refer to: Science, technology and mathematics the E12 series of preferred numbers E12 screw, a type of Edison screw the code name for Microsoft Exchange Server 2007 Siding Spring Survey code Transport Roads and trails European route E12 E12 European long distance path Ampang–Kuala Lumpur Elevated Highway (AKLEH), a fully elevated expressway in Kuala Lumpur, Malaysia Vehicles BMW E12 HMS E12, a United Kingdom Royal Navy submarine which saw service during World War I Spyker E12, a Dutch Spyker car Other uses Queen's Indian Defense, Encyclopaedia of Chess Openings code E12, a postcode district in the E postcode area E-12 equal temperament consisting of twelve equal semitones per octave