斜面
しゃめん · shamen · JLPT N1 · noun
slope
斜 — dipper 斗 + give 余 (phonetic)
斜 is a phonosemantic compound. The right side 斗 (a ladle or dipper) gives the meaning, since pouring from a dipper tilts it sideways. The left side 余 supplies the sound. From 'tilted ladle' the meaning broadened to 'slanting, oblique, askew.'
面 — enclosure 囗 + 自 (nose/face inside)
Originally a pictograph showing a face framed by an outline, with 自 (nose) inside representing the central feature of the face. The early meaning was 'face,' which extended to 'surface,' 'side,' and 'aspect.' In simplified Chinese, 面 also absorbed 麵, adding the meaning 'flour/noodles.'