'Un' means 'One' in French. It is also used to say 'a' when talking about something that is masculine. The feminine version is 'une'.
The French translation for "one" is "un".
You say un crayon in French.
'un but' (masc.)
un four is an oven in French
un sac is a bag in French.
un mois means 'a month' in French.
"un bus" is a bus in French.
a peacock is called "un paon" in French (do not pronounce the "o" in the word)
a jumper is called "un pull / un pullover / un sweat" in French
"J'ai un" in French translates to "I have a" in English.
a raincoat is 'un imperméable' or 'un manteau' in French.
A journey is "un voyage" or "un trajet" in French.