Webster's English Dictionary

monotone

mono.tone \'ma:n-*-.to-n\ \.ma:n-*-'ta:n-ik\ \-i-k(*-)le-\ n [Gk monotonos 
   monotonous] 1: a succession of syllables, words, or sentences on one 
   unvaried key or pi tch 2: a single unvaried musical tone  3: a tedious 
   sameness or reiteration  - monotone aj