Riddle #634

Question: I am a nice word composed of five letters, but the Romans would call me a numbers.

What am I?

Question: What kind of button won't unbutton?

Question: What do you get when you cross a cheetah and a burger?

Question: What tastes better than it smells?

Question: What goes in the water black and comes out red?

Question: What loses its head in the morning and gets it back at night?