The Heart of the Mid-Autumn Festival: You cannot separate mooncakes from the Mid-Autumn Festival (中秋节, Zhōngqiū Jié). They are to this holiday what turkey is to Thanksgiving or what a Yule log is to Christmas. The festival celebrates the harvest and the full moon, and sharing mooncakes under the moonlight is the central activity.
Symbol of Family Reunion: The most profound meaning of the mooncake is family unity. Its round shape symbolizes “reunion” and “completeness” (团圆, tuányuán). Families will often cut a single mooncake into wedges, with each family member receiving a piece, no matter how small. This act reinforces the idea that the family is a complete, unbroken circle. Even if family members are far away, they can look at the same moon and eat mooncakes, sharing a symbolic connection.
Comparison to Western Culture: A good comparison is the Christmas fruitcake or a Thanksgiving pumpkin pie, but with an added, deeply significant gifting component. While a pie is typically baked and shared at a family meal, boxes of mooncakes are a massive commercial industry focused on gifting. Exchanging elaborate boxes of mooncakes between friends, colleagues, and clients is a modern ritual that reinforces social and business relationships (关系, guānxi). It's a gesture of respect, appreciation, and wishing prosperity upon the receiver.