[Nikto-discuss] Allowed HTTP Methods means

[喻方]

Hello!
I am a new user of nikto, thanks for your explaination!
I don't the following message from nikto scaning.
+GET /: Allowed HTTP Methods: OPTIONS, TRACE, GET, HEAD, POST
+ GET /: Public HTTP Methods: OPTIONS, TRACE, GET, HEAD, POST

what is the  difference between Allowed HTTP Methods and Public HTTP Methods?
what is the mean of every message GET,HEAD?

Thanks!