Enraizó is the past tense of enraizar, which means "to take root" like a plant. It's a beautiful and powerful word that you won't hear every day.
In this classic song, MANA uses it metaphorically to create a stunning image: "Y su cuerpo se enraizó, en el muelle" (And her body took root on the pier). This suggests she waited so long for her love to return that she literally became a part of the pier, capturing the depth of her eternal wait and devotion.
This song tells a wild story, supposedly based on a real legend from San Blas, Mexico. It's about a woman whose lover sails away on a boat, promising to come back. She makes a promise too: "empapada en llanto ella juró que esperaría" (drenched in tears she swore she would wait). And boy, does she wait. For years and years, she stands on that same pier, wearing the same dress so he won't miss her when he returns.
The lyrics get really intense as time passes. Her hair turns white, and the townspeople start calling her "la loca del muelle de San Blás" (the crazy woman of the San Blas pier). She becomes so connected to the spot that her body literally "se enraizó, en el muelle" (took root on the pier). When people try to take her to an asylum, they can't move her. In the end, she stays there forever, becoming one with the sea, which the song calls her new love.