The difference between Lady abbess and Madam

Lady abbess is also noun with the meaning: a bawd, the mistress of a brothel.

Madam is also verb with the meaning: to address as "madam".

check bellow for the other definitions of Lady abbess and Madam

Lady abbess as a noun (rare, obsolete, euphemistic):

A bawd, the mistress of a brothel.

Madam as a noun (dated, _, in the UK):

Examples:

"Mrs Grey wondered if the outfit she was trying on made her look fat. The sales assistant just said, “It suits you, madam”."

"Later, Mrs Grey was sitting in her favourite tea shop. “Would madam like the usual cream cakes and patisserie with her tea?” the waitress asked."
Madam as a noun:

The mistress of a household.
Madam as a noun (colloquial):

A conceited or quarrelsome girl.

Examples:

"Selina kept pushing and shoving during musical chairs. The nursery school teacher said she was a bad-tempered little madam."
Madam as a noun (slang):

A woman who runs a brothel, particularly one that specializes in finding prostitutes for rich and important clients.

Examples:

"After she grew too old to work as a prostitute, she became a madam."