Rain is a constellation in the twenty-four solar terms.

The answer to this riddle is * * mouse * *. The explanation is as follows:

1. "The vernal equinox is one of the 24 solar terms and the middle stage of spring. At this time, there is more rain, and mice like to live in a dark and humid environment, so this sentence implies the existence of mice.

2. "Things in the home": Things in the home generally refer to family members. Rats are the only animals called "house mice" in the zodiac, so they can be regarded as the representatives of "things in the home". At the same time, "seeing solid" means being fixed and firm, and rats often move in fixed places, which also conforms to the meaning of "seeing solid".

Therefore, based on the above explanation, the answer to this riddle is mouse.