What does the word "devaluation of a currency mean" in a technical economic sense. Is it different from floating rate?
Devaluation of a currency occurs when the currency depreciates and is often associated with excess supply of the local currency do to overly dovish cental bank. The central back in 'printing' money as excess supply overwhelms demand.
This is due to the law of diminishing marginal returns. Each dollar that is printed is worth less than the previous one.