Where the shape comes from
A frog or toad seen from above, its wide body and splayed legs drawn crouched around a central line — a squat, broad creature caught in its characteristic pose. Almost entirely absent from everyday vocabulary now, it survives chiefly in 黾勉, to make a determined, sustained effort, an old classical expression that keeps only the character’s sound and shape, with nothing left of the frog in its meaning.
汉字 filed under 黽
No published character on HSK Guide is filed under this radical yet. 汉字库.