INTERFIX. An element used to unite words and bases: the THEMATIC VOWELS -i- in agriculture, -o- in biography, and -a- in Strip-a-gram are interfixed vowels; the middle words in editor-in-chief, writer-cum-publisher, Rent-a-Car, and Sun 'n Sand are interfixed words; -ma- and -ummy- in thingamabob/thingummybob are interfixed syllables. Such elements generally fit into the RHYTHM of the language as weak vowels and syllabic consonants. In late 20c English, thematic vowels proper sometimes overlap with such other interfixable elements as the indefinite article and the agentive suffix -er, as in: megalith, aquaphobic, Linguaphone, Funarama, SelectaVision, Select-a-game, Post-a-Book, Porta-phone, Rent-a-car, Comutacar. Such coinages are often stunt words created as commercial names. In pronunciation, the a-element in all of these items is a schwa, but in many cases the function of the a is unclear: in SelectaVision it could be thematic like the -e- in television, a reduction of -or in selector, an indefinite article (Select a vision), or a mix of these. The range of such usages is large: (1) Like -a- in megalith: Beat-A-Bug, Cup-a-Soup, gorillagram, Prismaflex, Relax-a-Dial, Rent-a-tux. (2) Like -e- in telephone: cineplex, Procretech, telecom. (3) Like -i- in carnivore: agri-biz, Chemi-Garded, Digipulse, flexitime, Healthitone, Multivite, NutriTime, VisiCalc. (4) Like -o- in cardiogram: biotech, Dento-Med, Film-O-Sonic, Fotopost, Frig-O-Seal, FructoFin, Thermoshell, Tomorrowvision. (5) Like -u- in acupuncture: AccuVision, CompuSex, Execu-Travel, Dentu Cream. (6) Like -y- in bathyscaphe: polywater, Skinnyvision. See BLEND, COMBINING FORM.