Where the shape comes from
Three ears of grain drawn standing at exactly the same height in a field — the picture is agricultural, but the meaning it yields is pure abstraction: things brought level, matched, made equal, before ripeness is ever a metaphor for anything else. It gives 齐全, complete, all present and correct, and 整齐, tidy, orderly, in disciplined ranks, and reduces to a single component, heavily compressed, in 剂, a dose or preparation measured out in equal portions, as in 药剂, medicine. As a family and place name it is read the same way, borne by the ancient state of Qi on the Shandong peninsula, one of the great powers of the Warring States.
汉字 filed under 齊
No published character on HSK Guide is filed under this radical yet. 汉字库.