The Spanish word 'lombriz' meaning 'earthworm' or 'worm' comes from the Vulgar Latin word 'lumbrix', which simply meant 'worm'. This Vulgar Latin term evolved from Classical Latin 'lumbricus', which specifically referred to an intestinal worm. Over time, the meaning broadened to include earthworms and worms in general as the word made its way into Spanish.

While 'lombriz' itself is a relatively basic Spanish word for 'worm', you might encounter its diminutive form 'lombricita' (little worm) or the related adjective 'lombriciento' (wormy), though these are less common.

The English word 'lumbricus' is directly related, though it's primarily used as a scientific term in biology and zoology, specifically in 'Lumbricus terrestris', the scientific name for the common earthworm. The English word 'lumber' is not related to this etymology, despite the similar sound.