祖 is a phono-semantic character. 礻, the side form of 示, points toward rites, spirits and offerings; 且 mainly supplied the ancient sound. Early writing connected ancestry closely with ritual, but the exact pictorial history of 且 is debated, so it should not be turned into a literal family picture. This ancient-form-inspired sketch keeps an altar-like 示 beside a tall, clearly separate 且.
A piece of culture
Remembering the generations before us 祖先 means “ancestors”. Families remember earlier generations in many different ways, from keeping photographs and telling stories to visiting graves during Qingming. Practices vary by region, religion and household; the shared idea is that a family story began before the people living today.