The word "twains" is a fairly uncommon word that refers to two similar things or people. It is often used in literature or historic writing to describe a pair of entities, such as "The Adventures of Huckleberry Finn" by Mark Twain, which follows the journey of two companions down the Mississippi River. Synonyms for "twains" include words such as "duo," "pair," "couple," "dyad," or "twin." These terms all imply a sense of twoness or duality, and can be used interchangeably with "twains" in many contexts. Whether describing friends, lovers, or fictional characters, these synonyms offer a variety of options for writers to describe familiar pairings.