Radical 17

Radical 17 is one of 23 of the 214 Kangxi radicals that are composed of 2 strokes.

It does not occur as a character on its own. In combination, it historically takes meanings such as "open mouth", "box", "frame", "hole". In contemporary use, it is the base radical of the following characters:

Also derived from the radical are the Simplified Chinese characters 击 "to hit" and 画 "to paint", without any historical connection to the radical.

幽 "deep, dark" is derived from radical 46, "mountain" 山 rather than radical 17.

As for the similar radicals 22 匚 and 13 冂, the name of radical 17 is purely descriptive of its shape, 下三框 "lower three-sided frame".