While shanties were historically understood as work songs, the word "shanty" has often been used in popular culture since the mid-20th century as a catch-all term that also includes songs supposed to have been sung during leisure time at sea, and even other songs about the sea or which vaguely inspire thoughts of the sea. Much of the historical shanty repertoire, being by definition designed to suit work, is less attractive as entertainment listening. The musical forms were highly repetitive, and the lyrics were quite often doggerel without any cohesive or preconceived composition. For these reasons, sea songs that were never or only exceptionally adapted as shanties—but which have engaging melodies and texts—have proved popular to 20th century audiences under the rubric of "shanties." Both these non-shanty sailor songs and the historical repertoire of shanties are typically performed with instrumental accompaniment—something that was rare or unheard of at sea in the case of authentic shanties.