What does it mean to dream about basement?
A basement commonly stands for what lies beneath the surface of you, memory, instinct, or things stored away and out of sight.
Four ways to read it
Each reading below comes from a named tradition and a cited source, so you can see where it came from and decide what fits your dream.
Freud
Freud would read the lower rooms as the place of buried material, wishes and memories pressed out of mind but still active below. What is hidden down there can surface in dreams. Note what you find when you descend.
After Freud, The Interpretation of Dreams (Brill trans., 1913), public domain.Jung
Jung often pictured the house as the psyche, with the basement as the deeper, older layers, the unconscious and what the self keeps below. Going down can mean meeting the shadow. Ask what waits in the lower room.
Jungian concept (our summary).Modern
Under the continuity view, a basement may reflect waking thoughts you have set aside, feelings stored rather than faced. A dark or cluttered cellar can echo unfinished business. Consider what you have been keeping out of sight.
Continuity hypothesis (our summary).Mythological
The descent into the lower world is a recurring journey in myth, a going-down to face the dead, the hidden, or the truth, before a return to the light. What lies beneath holds both danger and treasure. The descent changes the one who makes it.
Rosmerta Publishing editorial synthesis (after Bulfinch; Frazer).