sequence, number, grade, degree
苐 centers on ordered progression: a sequence, a numbered position, a grade, or a degree. The meanings all relate to steps in a series or levels of measurement.
苐 is a rare character whose historical development is uncertain. It visually contains 艹 (grass) over a form resembling 弟, but the exact origin and component roles are unclear.
The grass top 艹 suggests growth, and the lower part looks like a series of steps or levels. Imagine grass growing in distinct stages, each a numbered grade in a sequence.
For テイ, picture a teacher grading a sequence of test papers, marking each with a red 'T' for 'Tei': T -> テイ, and the grades form an ordered list.