From Latin glūten 'glue,' from PIE *glei- 'to stick' — a doublet of gluten.
A sticky substance used for joining things together.
From Old French glu 'birdlime, glue,' from Late Latin glūs, glūt- 'glue,' from Latin glūten 'glue.' The PIE root *glei- 'to stick, smear' also produced 'clay.' Medieval glue was typically made by boiling animal hides and bones. Key roots: *glei- (Proto-Indo-European: "to stick, smear, form into a ball").