bar, barre

Bar or bar means a rectangle or stripe--
He used a bar of iron as a lever to move the log.
The gold bar on his shoulder is an emblem of rank.

Bar or bar also means a tavern or saloon--
He walked down the street and turned into a bar.
The bar will be closing in ten minutes.

Bar or bar also means the  legal profession, or the actual railing in a law court, separating the spectators from the participants--
He took the bar exam, and is waiting for the results.
He is an attorney, but he has never argued at the bar.

Bar also means to lock, to get in the way of, or to prohibit--
"Get up and bar the door."
He tried to bar their exit by standing in their path.
The court may bar any further use of evidence obtained by hacking.

Bar is also a musical sign, as in sheet music--
Stop when you see the bar.

Barre or barre ( rhymes with bar ) means the rail used for ballet or dance practice--
She practiced at the barre for three hours every day for months.
The mirror on the wall behind the barre enables the dancers to see their movements.

Now that you know that, you can say--
"The new rules bar any practice at the barre after ten p.m."

Note--"Barre" ( bar ee, always capitalized )  is a city in Vermont--
They sent us a postcard from Barre.
Note # 2--"barré" ( bar ay ) describes a kind of striped fabric--
The dress is made of a red and white polyester barré.