'Un' means 'One' in French. It is also used to say 'a' when talking about something that is masculine. The feminine version is 'une'.
"Sur un" is French for on a.
You say un crayon in French.
un mois means 'a month' in French.
"un bus" is a bus in French.
un four is an oven in French
'un but' (masc.)
un sac is a bag 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
A journey is "un voyage" or "un trajet" in French.
un crâne is a skull in French.
un survêtement is a tracksuit in French.