The story
From book + worm. Compare West Frisian boekewjirm (“bookworm”), Dutch boekworm, boekwurm, boekenwurm (“bookworm”), Low German Bökerworm (“bookworm”), German Bücherwurm (“bookworm”), Danish bogorm (“bookworm”), Norwegian bokorm (“bookworm”), Faroese bókaormur (“bookworm”), Icelandic bókaormur (“bookworm”).
Etymology from Wiktionary, CC BY-SA 4.0.