An Etymological Dictionary of the German Language/Glas
Glas, n., ‘glass, tumbler,’ from the equiv. OHG. and MidHG. glas, n.; a common Teut. word unknown to the other Aryan groups; comp. OSax. gles, Du. glas, AS. glæs, E. glass; allied to OIc. gler, n., ‘glass,’ with the change of s to r, which proves the word to be primit. Teut. (*glaza- and *glasa- in Goth.). Hence it is not very probable that the Teut. word was borrowed, although glass itself was imported by the Phœnicians. The OTeut. term for amber (Lat. glêsum) is likewise primit. allied; comp. AS. glæ̂re, ‘resin of trees.’ See the following word.