A polite word used when leaving someone or ending a conversation. More formal than 'bye'.

Interjection. Can be a noun: 'We said our goodbyes.' Common phrases: say goodbye, bid goodbye, goodbye for now. 'Goodbye' originally comes from 'God be with ye' — a traditional farewell blessing.

The word 'goodbye' evolved from the phrase 'God be with you', which was shortened over centuries. It is more formal than 'bye' and often used in professional or formal situations. 'Farewell' is an even more formal alternative, often used in writing or emotional departures.