I thought the term "in one" came from vaudeville, but according to this page, it goes back even farther, to the days of minstrel shows:
"In One — An act or routine that works in the six-foot area between the footlights and the closed main show (number one) curtain. An act that needed that area plus the next six feet was "in two" since that area was in front of the number two curtain, and so on up to "full stage." While various theaters' stage dimensions might vary a bit, these specifications were standard ways of describing an act's space requirements, and were a primary consideration in planning the practical flow of a full program.
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"The "second part" was a series of specialty acts "in one" (played mostly in the front six feet of stage before the closed olio curtain). It would not be thought complete without a 'stump speech', a satirical monologue full of bumpkin malapropisms, jokes and puns, in a setting simulating a tree stump where people might pause to chat during a break from plantation work.
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"Olio Acts — Smaller numbers or acts performed "in one" during set changes for the major acts of the show. 'Olio' derives from 'oilcloth,' meaning cloth treated with oil or paint. The "olio drop," often painted with advertising for local businesses, hung 6 to 10 feet back from the footlights. Simple specialty acts would perform in front of the "olio drop" while the stage was being set for the next major act. Such acts might be called for with ads such as: "Wanted: Acrobatic, juggling, and other novelty acts, to work in olio." "
http://www.goodmagic.com/carny/vaud.htm
Updated On: 7/11/12 at 07:46 PM