1. Any word or phrase that is repeated consecutively in music more than once to hold an otherwise substanceless song together. Not to be confused with repeated choruses or lyrics in fade out. Most easily recognizable in the hip-hop genre.
2. Any word that is rhymed with itself as part of a lyric.
Rihanna's 'Rude Boy' is almost exclusively composed of word glue (61%). Only 161 words out of the 538 word song are considered to be free of word glue.
"Come here, rude boy, boy..."
"Come here rude boy, boy..."
"...Take it, take it, baby, baby, take it, take it, love me, love me..."
Another distilled example by the same artist:
"...under my umberella, ella, ella, eh, eh, eh;
under my umberella, ella, ella, eh, eh, eh;
under my umberella, ella, ella, eh eh eh;
under my umberella, ella, ella, eh eh eh eh eh..."
In comparison "One Week" by Barenaked Ladies is composed of 0% word glue.