Etherealization is a term used to describe the process of something becoming more spiritual or otherworldly. If you're in search of a synonym, you might consider words such as spiritualization, transcendence, or elevation. These terms can help convey the same sense of something becoming more ethereal or otherworldly. Other options might include words like refinement, purification, or enlightenment, which all suggest a process of improving or becoming more enlightened. Ultimately, the choice of synonym will depend on the context and tone of your writing, and you may need to experiment with a few different options to find the perfect fit.