To relieve or reduce emotional or mental stress; to relax, either in oneself or by helping another person to do so. She took a long walk in the park to destress after a hectic day at work.
To relieve internal stresses in a material by heat treatment or another controlled process. The glass panels were slowly cooled to destress them before installation.
To help (someone) relax and reduce stress. A soothing massage can destress tired employees at the end of the week.