Where the shape comes from
A crossroads seen from above: two roads meeting, the left arm of the junction drawn as 彳 and the right as 亍. It first named the road itself, then walking it, then anything that runs in a line — which is the háng of 银行, a row of shops, and of 一行字, a line of writing. Split it in two and the left half becomes the step radical 彳; keep it whole and it encloses 街 and 衔.
汉字 filed under 行
No published character on HSK Guide is filed under this radical yet. 汉字库.