The word "retreat" can refer to a few different concepts. In general, it means to withdraw or pull back from a certain place or situation. This can be done physically, like when a military force retreats from a battlefield, or metaphorically, such as stepping back from a stressful environment to take time for oneself. Retreat can also describe a peaceful place where someone goes to rest and recover, away from the hustle and bustle of daily life.
The word "retreat" comes from the Latin root "retractare," which means "to draw back." The transition into Middle French as "retraite" also contributed to its modern English form.