I was recently walking down the street around 7:00pm and a non-native English speaker said to me “Goodnight.”  I replied back to him, “good evening.”  This started me thinking about the important difference between the use of these two phrases “goodnight*” and “good evening” in English. It is important to know what each means in order to use each properly and so that you can say exactly what you intend.  Here is a general rule about these two similar but different greetings:

Goodnight = a phrase one uses at the end of the day or evening when one leaves someone for the last time for the day or when one goes to bed.  This is essentially a way of saying “goodbye.”  (Note: it is very uncommon for Americans to say “goodbye” when they are going to bed, they will most likely say “goodnight.”)

Good evening = a greeting often used in the evening, after approximately 5:00-6:00pm.  This greeting is used similarly to “good morning” or “good afternoon.” This is a greeting to be used when meeting someone or passing by someone.  This is essentially a way of saying “hello.” This phrase is generally not used when taking leave of someone although the similar phrase “have a good evening” can be used when leaving someone for the last time in a 24 hour period of time in the evening or night time.

Here is a little dialogue to help clarify the difference.

Clem: Good evening Terry, have you had dinner yet? Terry: Hi Clem, no I haven’t, but I have too much work to do to go out to dinner. Clem:  That’s too bad.  I was hoping you would join me for a bite to eat. Terry: I’m sorry I can’t this evening. Clem: Well, good luck with all your work.  Goodnight. Terry: Thank you. Goodnight, enjoy your dinner.

*”Goodnight” is often also spelled “good night”, though it is my understanding that goodnight (as one word) is the proper form of the word as a greeting.  Sometimes this greeting is also written as “good-night.” These three versions all generally have the same meaning.