aid, help
佽 centers on providing support or assistance: giving aid or help to someone.
佽 combines 亻 (person) with 次, which likely contributes the sound and may relate to ordering or arranging help.
A person 亻 standing beside 次 (next in line) is ready to offer aid or help when needed.
For シ, imagine a person helping by handing over a sheet of instructions: sheet -> シ, and the person 亻 provides aid.