Motif (narrative) in the context of "Perseus and Andromeda"

A literary trope is an artistic effect realized with figurative language – word, phrase, image – such as a rhetorical figure. In editorial practice, a trope is "a substitution of a word or phrase by a less literal word or phrase". Semantic change has expanded the definition of the literary term trope to also describe a writer's usage of commonly recurring or overused literary techniques and rhetorical devices (characters and situations), motifs, and clichés in a work of creative literature.

In Greek mythology, Andromeda (/ænˈdrɒmɪdə/; Ancient Greek: Ἀνδρομέδα, romanized: Androméda or Ἀνδρομέδη, Andromédē) is the daughter of Cepheus, the king of Aethiopia, and his wife, Cassiopeia. When Cassiopeia boasts that she (or Andromeda) is more beautiful than the Nereids, Poseidon sends the sea monster Cetus to ravage the coast of Aethiopia as divine punishment. Queen Cassiopeia understands that chaining Andromeda to a rock as a human sacrifice is what will appease Poseidon. Perseus finds her as he is coming back from his quest to decapitate Medusa, and brings her back to Greece to marry her and let her reign as his queen. With the head of Medusa, Perseus petrifies Cetus to stop it from terrorizing the coast any longer.

As a subject, Andromeda has been popular in art since classical antiquity; rescued by a Greek hero, Andromeda's narration is considered the forerunner to the "princess and dragon" motif. From the Renaissance, interest revived in the original story, typically as derived from Ovid's Metamorphoses. The story has appeared many times in such diverse media as plays, poetry, novels, operas, classical and popular music, film, and paintings. A significant part of the northern sky contains several constellations named after the story's figures; in particular, the constellation Andromeda is named after her.

The Motif-Index of Folk-Literature is a six volume catalogue of motifs, granular elements of folklore, composed by American folklorist Stith Thompson (1932–1936, revised and expanded 1955–1958). Often referred to as Thompson's motif-index, the catalogue has been extensively used in folklore studies, where folklorists commonly use it in tandem with the Aarne–Thompson–Uther Index (ATU), an index used for folktale type analysis.

The motif-index and the ATU indices are regarded as standard tools in the study of folklore. For example, folklorist Mary Beth Stein said that, "Together with Thompson's six-volume Motif-Index of Folk-Literature, with which it is cross-indexed, The Types of Folktale constitutes the most important reference work and research tool for comparative folk-tale analysis.” Alan Dundes, who was an outspoken critic, also said substantially the same thing, without confining the application to comparative studies: "[the indices] constitute two of the most valuable tools in the professional folklorist's arsenal of aids for analysis".

The mad scientist (also mad doctor or mad professor) is a stock character of a scientist who is perceived as "mad, bad and dangerous to know" or "insane" owing to a combination of unusual or unsettling personality traits and the unabashedly ambitious, taboo or hubristic nature of their experiments. As a motif in fiction, the mad scientist may be villainous (evil genius) or antagonistic, benign, or neutral; may be insane, eccentric, or clumsy; and often works with fictional technology or fails to recognise or value common human objections to attempting to play God. Some may have benevolent intentions, even if their actions are dangerous or questionable, which can make them accidental antagonists.

The world tree is a motif present in several religions and mythologies, particularly Indo-European, Siberian, and Native American religions. The world tree is represented as a colossal tree which supports the heavens, thereby connecting the heavens, the terrestrial world, and, through its roots, the underworld. It may also be strongly connected to the motif of the tree of life, but it is the source of wisdom of the ages.

Specific world trees include Égig érő fa in Hungarian mythology, Ağaç Ana in Turkic mythology, Kenac' Car in Armenian mythology, Modun in Mongol mythology, Yggdrasil in Norse mythology, Irminsul in Germanic mythology, the oak in Slavic, Finnish and Baltic, Jianmu (Chinese: 建木; pinyin: jiànmù) in Chinese mythology, and in Hindu mythology the Ashvattha (a Ficus religiosa).

The Holy Grail (French: Saint Graal, Breton: Graal Santel, Welsh: Greal Sanctaidd, Cornish: Gral) is a treasure that serves as an important motif in Arthurian literature. Various traditions describe the Holy Grail as a cup, dish, or stone with miraculous healing powers, sometimes providing eternal youth or sustenance in infinite abundance, often guarded in the custody of the Fisher King and located in the hidden Grail castle. By analogy, any elusive object or goal of great significance may be perceived as a "holy grail" by those seeking such.

A mysterious "grail" (Old French: graal or greal), wondrous but not unequivocally holy, first appears in Perceval, the Story of the Grail, an unfinished chivalric romance written by Chrétien de Troyes around 1190. Chrétien's story inspired many continuations, translators and interpreters in the later-12th and early-13th centuries, including Wolfram von Eschenbach, who portrayed the Grail as a stone in Parzival. The Christian, Celtic or possibly other origins of the Arthurian grail trope are uncertain and have been debated among literary scholars and historians.