The word interferometer is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 21
Highest Scoring Words With Friends™ Play In The Letters interferometer
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Seven Letter Word Alert: (34 words)
emitter, enterer, ferment, fermion, ferrite, firemen, foremen, freemen, fretter, fritter, inerter, merrier, miterer, netform, oftener, omitter, onetime, reefier, reenter, referee, refiner, reinter, remoter, retimer, retiree, retirer, teenier, tentier, termite, terrier, terroir, torment, torrent, trireme