? Obs. [mod. f. Gr. ἠχώ ECHO, or ἧχος sound + -μετρία measuring. Littré has Fr. échométrie ‘art de calculer, de combiner la réflexion des sons,’ = sense 1 below.]

1

  1.  ‘The art of making vaults or arches so as to produce an artificial echo.’

2

1818.  in Todd.

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  2.  The art of measuring the duration of sound.

4

1847.  in Craig.

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