1.
front and back; both sides
The two physical surfaces of something, such as fabric or paper.
2.
two-facedness; duality; discrepancy between appearance and reality
The contrast between one's public persona and true nature, or between what is shown and what is hidden.
Related Words
Related:
二面性 (dual nature)
Related:
内外 (inside and outside)
Related:
上下 (top and bottom)
Related:
左右 (left and right)