body, group, class, unit
軆 centers on a physical body or a structured whole: a living body, a group of people, a class of things, or a unit within a larger system.
軆 is a variant form of 體 (body). It combines 身 (body) with 豊, which likely contributes the sound and reinforces the idea of a physical form or vessel.
The left side 身 means body, and the right side 豊 looks like a full vessel. Imagine a body as a container that holds a person's life and defines their physical form.
For タイ, picture tying a ribbon around the body to mark it as a single unit: tie -> タイ, and the body is one complete group.