Definition of the word nod off

The origin of the phrase "nod off" can be traced back to the early 19th century in English-speaking countries. The word "nod" in this context refers to a deliberate lowering of the head as a sign of acknowledgement, agreement, or acceptance. The term "off" here indicates departure or withdrawal, possibly from a particular place or situation. The expression "nod off" is a figurative usage of these words, and it describes the process of falling asleep. The idea is that just as a person nods as a way of signifying agreement, they can also nod in such a way that it seems they are dozing off, a subtle sign that sleep is approaching. The Oxford English Dictionary (OED) provides an early example of the use of the phrase "nod off" in an 1833 publication by the English author Charles Dickens. The OED defines the expression as "to fall asleep gently and gradually" and notes that its usage has become a commonly understood idiomatic expression in English language. In summary, "nod off" is a phrase that combines two everyday words, "nod" and "off," to create a new expression meaning the act of falling asleep gently and gradually. This usage originated in the early 19th century and has since become a common idiom in the English language.