“Lyric” is not a medieval term, but one that entered English critical discourse in the sixteenth century from classical genre theory and was later assimilated to Romantic theories of art as personal expression. The term now conventionally “signifies either a poem expressing personal emotion, or the words of a song” (see the Literary Encyclopedia entry on “Lyric”), but it is used more loosely in discussing medieval English literature to refer to any relatively short poem of the period, whether or not it expresses personal emotion and regardless of whether we know it was set to music. Only a very small number of lyrics from before ca.1400 survive with music, but it is possible that some of those that do not were once s…
Phelpstead, Carl. "Middle English Lyric 1100-1500". The Literary Encyclopedia. First published 02 November 2004; last revised 30 November -1.
[http://www.litencyc.com/php/stopics.php?rec=true&UID=1414, accessed 21 April 2015.]