How to say "flank" in Japanese

• 側面そくめんJLPT N1approx.Common
  nounFor 'flank' as the side of a thing, not of a body: the side of a building, vehicle, mountain, or military formation. It also covers 'profile' and, figuratively, a secondary aspect of a matter.
  鳥類ちょうるいの発声はっせいにおいて真しんに驚異的きょういてきな点てんは、鳴管めいかんの２つの側面そくめんが独立どくりつして動うごくことができるということである。↗

  The truly remarkable feature of sound production by birds is that the two sides of the syrinx can act independently.
• 脇わきJLPT N3approx.Common
  nounFor the bodily 'flank': the side of the torso around the armpit, as when something is tucked under one's arm. Its 'side' sense means 'beside, next to', not the surface of an object.
  彼かれがブリーフケースを脇わきに抱かかえてやってくるのが見みえた。↗

  I saw him coming with his briefcase under his arm.

Choose 側面 for the flank of a thing — a building, vehicle, or mountain — and for 'profile' or figurative 'side' senses; choose 脇 for the flank of a body, the side of the torso around the armpit.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 側面そくめんside
• 脇わきarmpit
• 脇腹わきばらside (of the torso)
• 側背そくはいflank
• 側腹そくふくflank
• 横っ腹よこっぱらside
• 横腹よこばらside
• 横合いよこあいside