Two readings split the meanings. First tone fāng covers lanes, wards and memorial gates: 牌坊, 街坊. Second tone fáng means a workshop or mill, as in 磨坊. The everyday word 作坊, workshop, takes a neutral tone.
history
In ancient Chinese cities, 坊 were walled residential wards with gates that closed at night. Many old Beijing street names preserve 坊.
土 (earth) supplies the indexing radical. A 坊 is a neighbourhood ward or a memorial gate, both things built on the ground and marked off as plots of land. The earth radical groups it with 城 (city), 坝 (dam), 场 (yard) and other man-shaped pieces of terrain.
方 supplies the sound, unchanged in this reading. It also doubles as a faint semantic: wards were rectangular precincts in the old city grid. The same phonetic series gives 房 (house), 防 (defend), 访 (visit) and 仿 (imitate).
