Act
2 of the 6 encyclopedias on this shelf carry an entry for Act. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
in the presentation of drama, one of the main divisions of a play, in which a definite portion of the action is completed. The divisions of drama into act and scene may mark a change of time or place. They give relief to both actors and audience from the strain of a long play, and also afford opportunity for change of costume and scenery. The unities of the Greek drama made separation into acts unnecessary. The Roman theater first adopted the division of a play into acts, and made five the regular number. Horace mentions this as a fixed rule, and it was obeyed by all dramatists of the Renaissance. Shakespeare, who paid little attention to any of the accepted rules of dramatic art, invariably divides his dramas into five acts. In light comedy, the rule is no longer regarded as essential; but in tragedy, where the action is weighty, there seems to be a real reason for the five acts. In every great action, there are naturally three parts, the introduction, the climax, and the conclusion. By presenting the introduction, or causes leading to the climax, in two acts instead of one, the characters are better developed, the interest is deepened, and the climax, being in a measure anticipated, is more impressive. So two acts leading from the climax to the final catastrophe allow the mind of the spectator to grasp more fully the sadness and horror of the situation, and thus those emotions which real tragedy should arouse are more deeply stirred. See Drama ; Tragedy ; Comedy ; Scene ; Stage
Collier's New Encyclopedia (1921)
in dramatic language, a portion of a play performed continuously, after which the representation is suspended for a little. As early as the time of Horace there were five acts in a drama, but this number is frequently modified on the modern stage. In parliamentary language, an act of congress, legislature, etc. In law: (1) Anything officially done by the court, as the phrases "Acts of Court," "Acts of Sederunt," etc. (2) An instrument in writing for declaring or proving the truth of anything.
What Has Changed in the Last Century
Aiton's Encyclopedia argued in 1910 that five acts had a "real reason" in tragedy, and that Shakespeare "invariably divides his dramas into five acts." Both claims have since been revised: modern scholarship holds that the act divisions in Shakespeare were largely imposed by editors, absent from many of the early quartos and regularized in printed editions from Nicholas Rowe's of 1709 onward, with the plays themselves acted more or less continuously. Collier's 1921 note that the five-act number "is frequently modified on the modern stage" proved the better forecast: the twentieth century settled on two acts with a single interval for most plays and musicals, and on a three-act shape as the standard vocabulary of screenwriting, where "Act Two" describes a stretch of story rather than anything a curtain marks.
Written for this edition, 2026.