メン, ベン, おも, おもて, つら, お, ずら, ほおつき, も
mask, face, features, surface
JLPT3 G3 S9 F186
The relevant seal inscription form combines 首 neck/head + a line# adhering to and nearly surrounding it, suggesting a *mask* adhering closely to and partially obscuring the *face* → *surface*; *aspect* → *turn (a face) to*; *look away*; *side*; *direction* → *counter* (for flat objects).
[Full Kanji Etymology List]