From Longman Dictionary of Contemporary Englishgood eveninggood eveningused to greet someone when you meet them in the evening → evening
Examples from the Corpus
good evening• Have a good evening. 1904 How can you, you have class tomorrow night?• Dearest Timothy: It is a good evening to sit in this pleasant room and write a letter.• Ah, good evening, Lestrade!• We exchange slightly embarrassed good evenings with them as we leave.• A bad morning, a good afternoon and - perhaps - an even better evening.• Behind the glass I see her tell everyone good evening.• A policeman walked by, wished me good evening and ushered a warning.• But for now from all the team, have a very good evening.good eveninggood ˈevening ●●● S3 formal HELLOused to say hello when you are greeting someone in the evening, especially someone you do not know → good afternoon, good morning, good nightRegisterIn informal everyday English, people often just say Evening. If you don't want to sound formal or informal, you can just say Hello:Evening, Tom. 