A retreat is a seclusion for spiritual self-exploration and spiritual practice. A suitable environment could be a monastery or a specially established retreat center.
I personally see a retreat as a collective word for deepening your life, living more substantively in daily life. For this we also do this with camping/cottages so that the Retreat becomes one whole with your Life. Within this collaboration, the lessons, walks, exercises and meditations are integrated and lived. This is also the reason that you can connect wherever you want. In the meantime you are in a field which in itself promotes peace and insight through its form, elements and intention. For a conscious seeker, a retreat is indispensable to gain insight, awake and deepening life.