What's the difference between "knock down" and "knock out?"

Native speaker’s answer
Rebecca
Both of these are boxing expressions. Losing balance without losing consciousness is referred to as being "knocked down." When the fighter becomes unconscious from a powerful strike, he's referred to as having been "knocked out" or "KO-ed." The singer here says she is knocked down, but she is back on her feet so she isn't knocked out. Essentially, she was given a strong blow but is still here, fighting. Ex: My opponent's blow knocked me out. Ex: Failing in love always knocks me down.