Greetings

Olá! Bom dia! It's time to learn portuguese greetings.

Olá	Hello
Bom dia	Good morning
Boa tarde	Good afternoon
Boa noite	Good evening Good night
Prazer em conhecê-lo(a)	Nice to meet you
Desculpe	Sorry
Com licença	Excuse me
Até logo	See you later
Tchau	Bye
Adeus	Good bye
Até amanhã	See you tomorrow
Até hoje a noite	See you tonight

Bom dia - it's the most common greeting. It's used from dawn 'til noon. You can also say "Tenha um bom dia" (have a nice day) in any part of the day.

Boa tarde - It's used from noon 'til nightfall.

Boa noite - It's used both as good evening and good night. Use this from nightfall 'til dawn.

Prazer em conhecê-lo(a) - When you're talking to a man (or a boy), you'll say "Prazer em conhecê-lo". If your're talking to a woman (or a girl), then you'll say "Prazer em conhecê-la". What if you're talking to more than one person from both sex? Well, then you're gonna say "Prazer em conhecê-los".

Com licença - You're probably thinking: 'what in the world is the ç letter?!'. Don't worry about it, pronounce it as a double 's' in portuguese or as 's' in the english word 'salt'.

Até amanhã - The 'é' is pronounced as 'e' in the english word 'hotel'. The 'ã' is pronounced exactly as the first 'u' in the english word 'uncut'.

Lot of doubts, huh? Don't stay in ignorance, ask your question in the comments section and I'll be glad to help you. Soon, I'll explain how to pronounce the letters with accent, like 'ã', 'é', 'á', etc.