Lady Plural. Woman is singular. Woman Women.
ˈleɪdɪ. In fact some of the most common English nouns have irregular plural forms such as womanwom en and childchild ren. A woman regarded as having the characteristics of a good family and high social position.
For lady the possessive singular is a different word than the possessive plural when written but it is pronounced the same.
Some nouns cannot be made into plurals just by adding an s es or changing f into a ves. The voice of Lady is feminine and the article die. As a modifier of a plural noun woman like man is exceptional in that the plural form women is used. As forms of address both nouns are used in the plural Ladies and gentlemen thank you for your cooperation but only lady occurs in the singular.