A man wanted to enter a club. Every member knew the password.

The man was hidden beside the wall and tried to hear the password.

A member came, Watchman said TWELVE , Member replied 6, Watchman opened the door.
...

Another member came, Watchman said SIX, Member replied 3, Watchman opened the door

Man thought he got the password. He went to the door, Watchman said EIGHT, Man replied 4, Watchman didn't open the door.

What was the password?