Meaning

noun a musical composition of a free form usually incorporating several familiar themes

originBorrowed from Italian fantasia (“imagination, fancy, fantasy; musical composition with improvisational characteristics”), from Latin phantasia (“fancy, fantasy; imagination”), borrowed from Ancient Greek φᾰντᾰσῐ́ᾱ (phăntăsĭ́ā, “appearance, look; display, presentation; pageantry, pomp; impression, perception; image”), from φᾰ́ντᾰσῐς (phắntăsĭs) + -ῐ́ᾱ (-ĭ́ā, suffix forming feminine abstract…

Etymology from Wiktionary, CC BY-SA 3.0