trope 
(trōp)
(trōp)n.
1. A figure of speech using words in nonliteral ways, such as a metaphor.
2. A word or phrase interpolated as an embellishment in the sung parts of certain medieval liturgies.
[Latin tropus, from Greek tropos, turn, figure of speech; see trep- in the Appendix of Indo-European roots.]
tropi·cal (trōpĭ-kəl) adj.