Bye is used to indicate that the person is leaving. It is a shortened way of saying goodbye.
Bye is a word that we use to indicate that we are leaving. It is commonly used to say farewell to somebody. Whenever people are parting ways, i.e. going their own way they use goodbye.
Imagine a scenario, where you are meeting your friend to hang out. After you guys hang out doing whatever it is you like to do for fun, it is now time for you to go back to your own homes. So when leaving each other to go home, you need to say farewell to the other. Otherwise, it would seem just rude if you turn around and walk away without saying some sort of a farewell to each other. Hence, at this time, bye seems like a good word to use. Of course there are other ways of saying farewell, including ‘farewell’, ‘bye’, ‘see ya’, ‘see you later’, etc. Some people also prefer to hug or shake hands, in addition to or even instead of saying something.
The term bye is used a farewell, but the implication is not of a final farewell, rather it implies a temporary farewell. Hence, bye just means that we are parting ways now but we shall meet again. However, when that will be is not certain. It could be in a few minutes, a few hours, tomorrow, a few days, weeks, or months, but the intention of this farewell is that it is not permanent.
The word bye is a contraction of the word ‘goodbye’, which is again a parting word. Basically, ‘bye’ is considered as an informal way of saying ‘goodbye’. Hence, it commonly used only with friends and family, rather than in formal situations. However, this trend is now rapidly changing and ‘bye’ is replacing ‘goodbye’ as the go to farewell word. In fact, many people don’t use ‘goodbye’ at all.
‘Goodbye’ in turn is a contraction of the phrase ‘God be with you’, which is basically a prayer that we are parting on good terms and may god take care of you. As this phrase seemed too overloaded, the contraction ‘Goodbye’ came into play, as is the case with language.