Try these for some details:
$ type hash
$ man 1p hash
and a well explained article about hash is this
. Here is an excerpt:
$ type foo
foo is hashed (/usr/local/bin/foo)
This is reporting that the shell has saved the meaning of foo in a hash table as /usr/local/bin/foo (...). Caching the command in a hash table is an optimization that saves the shell from having to search $PATH every time.