There are several synonyms for the phrase "first act" in the context of theater and literature. Some alternatives include "opening scene," "initial sequence," "prelude," "introduction," and "prologue." These terms all refer to the beginning of a play, book, or other performance, and may be used interchangeably depending on the situation. Each phrase carries a slightly different connotation, with "prologue" implying a preface or explanatory material, and "opening scene" focusing specifically on the first visual and spoken elements of a performance. Choosing the right synonym can help make your writing or speech more precise and effective in conveying your intended meaning.