Meaning of те as in Здравствуйте

To greet somebody you can say Здравствуй or you can add те and say Здравствуйте.  From my research it appears that те alone is not a word, but I might be wrong.  What is the meaning of те?

Здравствуйте Ivan!

-те is not a word, but rather an ending. It is used in verbs in their Imperative form. There's more about Imperatives in section 7.7
Both Здравствуй and Здравствуйте are Imperative forms of the verb здравствовать

Thank your reply.  I suspected that -те was ending.  This is good to know.

For the benefit of those who are wondering exactly what an imperative verb is:

"Imperative verbs are verbs that create an imperative sentence (i.e. a sentence that gives an order or command). When reading an imperative sentence, it will always sound like the speaker is bossing someone around."

Imperative forms are also used to express requests, invitations, instructions and advice. 
извините (I'm sorry) and давайте (let's..) are also imperatives 

This is good to know.  Thank you for mentioning this.