四大

1. • the four elements: earth, water, fire, and wind (Buddhism)
2. • the four freedoms: speaking out freely, airing views fully, holding great debates, and writing big-character posters, 大鸣大放 dàmíngdàfàng, 大辩论 dàbiànlùn, 大字报 dàzìbào (PRC)

Character by character

• 四(sì)four
• 大(dà)big