un tabier doesn't mean anything, un tablier means un apron
I hope you mean 'What do the initials 'UN' mean - United Nations.
It's "un accomplissement" and it does mean an accomplishment or fulfillment
'en un' = 'in a'
un yaourt is a yogurt
Un rossignol is a nightingale.
un serpent is a snake in French.
Un cheval is a horse.
Un fou is a madman.
Un is a masculine article and une is a feminine article. They both mean one, or a. Example: un chat: a cat
un fils unique mean the only son
Translation: Un Tigre