enshrine, worship
祀 centers on ritual dedication to a deity or spirit: enshrining something sacred and performing acts of worship.
祀 combines 示 (altar, religious ceremony) with 巳, which likely contributes the sound and may represent a snake or a cyclical sign, but the exact historical role of 巳 is uncertain.
At the altar 示, a coiled snake 巳 is enshrined and worshipped. Imagine a sacred snake resting on the altar as the focus of a ritual.
For シ, picture a worshipper at the altar saying 'she' to refer to the enshrined deity: she -> シ, and the altar is dedicated to her.