ソク, かわ, がわ, そば

side, lean, oppose, regret

JLPT3 G4 S11 F216

As per # (beside): → *side* → *move (toward)*; *lean*; *one of two facing sides* → *raise* (← raise the head so as to face another person directly). Here, has no semantic function, being used simply to create a derivative character conveying meanings that dropped from the original one.

[Full Kanji Etymology List]