The noun RETREAThas 6 senses:
1. (military) withdrawal of troops to a more favorable position to escape the enemy’s superior forces or after a defeat
2. a place of privacy; a place affording peace and quiet
3. (military) a signal to begin a withdrawal from a dangerous position
4. (military) a bugle call signaling the lowering of the flag at sunset
5. an area where you can be alone
6. withdrawal for prayer and study and meditation
The meaning of a Spiritual Retreat in Wikipedia is that:
The meaning of a spiritual retreat can be different for different religious communities. Spiritual Retreats are an integral part of many Buddhist, Christian and Sufi (Islamic) communities.
In Buddhism, retreats are seen by some as integral for reconnection to one’s self.
Retreats are also popular in Christian churches, and were established in today’s form by St. Ignatius of Loyola (1491-1556), in his Spiritual Exercises. Ignatius was later to be made patron saint of spiritual retreats by Pope Pius XI in 1922. Many Protestants, Catholics and Orthodox Christians partake in and organise spiritual retreats each year.
Meditative retreats are an important practice in Sufism, the mystical path of Islam. The Sufi teacher Ibn Arabi‘s book Journey to the Lord of Power (Risālat al-Anwār) is a guide to the inner journey that was published over 700 years ago.