The idiom “flat on one’s back” has both a literal and figurative meaning: Literal meaning : Lying horizontally on your back, usually due to illness, injury, or exhaustion. Figurative meaning : Being incapacitated, bedridden, or unable to function because of sickness, fatigue, or overwhelming circumstances. Example: “I was flat on my back with the flu all weekend.” 🕰 Origin or Background The phrase “flat on one’s back” has been in use since at least the late 19th century. It likely grew from the simple physical description of someone bedridden—lying flat, unable to rise. In boxing, a fighter “flat on his back” is knocked out cold, which reinforced the idiom’s sense of helplessness. In literature and journalism, it became a vivid way to describe illness, injury, or even financial ruin. 💬 Common Usage in Everyday English You’ll encounter “flat on one’s back” in contexts like: Casual conversation : “I was flat on my back with a cold.” Workplace : “Our lead engineer is flat on his ba...