A Dictionary of Music and Musicians/Bis
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BIS (Fr.), that is, 'twice,' a cry more in use abroad than here, and equivalent to Encore. The French even have a verb, bisser, to repeat.
When written, as it sometimes is in MS. music, over a phrase or passage, it signifies that the notes are to be repeated; the same thing would be effected by dots of repetition at the beginning and end of the phrase.