hum·mer /ˈhʌmɚ/
  發嗡嗡聲的東西,蜂鳥
  Hum·mer n.
  1. One who, or that which, hums; one who applauds by humming.
  2. Zool. A humming bird.
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  hummer
       n 1: a singer who produces a tune without opening the lips or
            forming words
       2: (baseball) a pitch thrown with maximum velocity; "he swung
          late on the fastball"; "he showed batters nothing but
          smoke" [syn: fastball, heater, smoke, bullet]