uno is the word for the number one. but also un, uno, and una are all articles meaning "an/a". una is feminine and used with feminine words (ex. una zebra- a zebra) while un and uno are masculine. un is used most of the time. (ex. un telefonino- a telephone) while uno is the exception. the exception is when a word starts with ps, st, or z. (ex. uno stereo- a stereo) i hope this helped (: and if you ever have any more questions just message me, i have an two copybooks and a textbook that i can help you to learn with ^.^