背面|はいめんhaimen[0]heiban (flat)

1. no-adjectiverear; back; reverse

• Synonym裏側うらがわNeutralThe reverse or back side of an object, also hidden circumstances; more colloquial than 「背面」 and used in a wider range of situations.
• Synonym裏面りめんNeutralThe reverse of paper, coins and the like, also the dark side or inside story; 「背面」 focuses on the back face of an object.
• Synonym裏手うらてNeutralThe back of a building or place, as in 「家の裏手」; mostly for buildings and locations rather than objects.
• SynonymバックNeutralLoanword for the back or background, also backing or support; 「背面」 is the back face of an object.
• SynonymリアNeutralLoanword mostly for the rear of a car, as in 「リアウインドウ」; industry jargon.
• Synonym後ろうしろNeutralThe most everyday word for behind or the back; 「背面」 is more written and stresses the back face of an object.
• Synonym背後はいごNeutralBehind someone, also figuratively behind the scenes, as in 「背後関係」; stresses what is at a person's back or hidden.
• Related後部こうぶNeutralThe rear part of a vehicle or object, as in 「後部座席」; a section rather than a face.
• Related背中せなかNeutralThe back of a person or animal, the most common everyday word; 「背面」 is for the back of an object.
• Related後方こうほうWrittenOld word for the rear or behind, rarely used today; say 「後ろ」 instead.
• Related後ろ側うしろがわNeutralThe side at the back; colloquial and direct. Largely interchangeable with 「背面」.
• Related背部はいぶWrittenThe back of a person or animal; medical and written usage. 「背面」 is mostly for objects.
• Related後尾こうびNeutralThe tail end of a line of people or vehicles, as in 「最後尾」; stresses position in the queue.
• Related後面こうめんWrittenThe back face; rare even in writing. In everyday use say 「後ろ」 or 「背面」.
• Related後背こうはいWrittenThe area behind or to the rear; mostly in compounds like 「後背地」. Written style, seldom used alone.
• Antonym正面しょうめんNeutralAntonym: the front of an object, the face turned toward you; the opposite of 「背面」.
• Antonym前面ぜんめんNeutralAntonym: the front face, the opposite of 「背面」. Also in 「前面に出す」, to put something in a prominent place.

For the back face of an object, 「背面」 is the default; in everyday speech 「後ろ」 or 「裏側」 works too. Use 「背後」 for the space behind a person (also behind the scenes), 「背中」 for the body's back, and 「後部」 or 「リア」 for the rear of a vehicle. 「裏面」 is the reverse of paper or coins, 「裏手」 the back of a building, and 「後ろ側」 is largely interchangeable with 「背面」. The opposite side is 「正面」.

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

1. 物体ぶったいの後あとの面めん。
2. 物事ものごとの裏うらに隠かくされた別べつの面めん。