Definition and Examples
In English, the word “to meet” can mean meeting someone for the first time as well as meeting someone you’ve met before. In German, there are separate words for these situations:
kennenlernen — to meet for the first time / to get to know
treffen — to meet (up) with someone you already know
So, during a formal introduction it is normal to say:
Nett Sie kennenzulernen. Nice to meet you.
Es hat mich sehr gefreut, Sie kennenzulernen. It was nice meeting you.
And this is how you say when you’re meeting someone you know:
Ich treffe heute Freunde. Today I’m meeting friends.
Incidentally, if the word kennenlernen is too long for you, it is also acceptable to write two words: kennen lernen.