級
キュウ, しな

class, rank, grade

JLPT1 G3 S9 F785

As per 及# (press on) + 糸 thread → pieces of fabric of various quality, pressing on each other in being inspected → *rank*; *class*; *grade* (← levels of quality) → *head* (← make promotions contingent on the taking of heads on the battlefield).

[Full Kanji Etymology List]