Invitation vs. invite

[Andreana]

Hi, what is the difference between an invite and an invitation? Is is correct so say Thank you for the invite or Thank you for the invitation?
A
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[Cesar]

http://yahooligans.yahoo.com/reference/dictionary/entry/invite

Invite, as a noun, is informal.

I never use it as a noun; it doesn't sound correct to me.

Regards.