Radical礻shì：示字旁儿(shìzìpángér) or 示补儿(shìbǔér) -- ancestor, veneration, or spirit

The character 示 looks like an altar or offering table, the top stroke depicting the offered goods, meaning ancestor, veneration, or spirit.  Transformed from 示, 礻is used as a radical, which always appears in the left half of characters. For example, 神 "spirit" has radical 礻 plus 申 shēn as a phonetic marker. Similarly, 祖 "ancestor" on the other hand has radical 礻 plus 且, a pictograph of a stand with shelves for offerings to ancestors. Here are more examples, 

Radical map