背后(bèi hòu) - behind, at the back; behind someone's back in Mandarin

背后 is a place word meaning behind or at the back of something. Grammatically it behaves like 后面, and the two are often interchangeable for physical position, but 背后 keeps a hint of the human back in it, so it suits people and upright objects better than, say, a queue.

Two senses beyond the literal are worth knowing. First, doing something 在背后 means doing it behind someone's back, and it is nearly always disapproving: 在背后说坏话 is exactly the English gossip. Second, 背后 marks a hidden cause, as in 这件事背后 for what lies behind an incident, which is standard in journalism.

The trap is 背 itself, which is a polyphone. Read bèi it is the noun back and appears in 背后 and 后背; read bēi it is the verb to carry on one's back, as in 背包 for a rucksack. There is also 背 bèi meaning to recite from memory, as in 背课文.