Ann has a great piece in the (newly launched and very beautiful) New Republic about ladies who call each other, well, ladies. Sifting through the intergenerational interpretations, rap lyrics and colloquialisms, she writes,

….the word “lady” has become core vocabulary of feminism in the age of irony. With its slippery meaning—associations range from grandma’s lavender-scented powder to the raunchiest of rap lyrics—it encapsulates the fundamental mutability of modern feminism.

And goes further,

…..“lady” splits the difference between the infantilizing “girl” and the stuffy, Census-bureau cold “woman.” (Both still have their place—just not in the witty conversation that young feminists want to be having.) It’s a way to stylishly signal your gender-awareness, without the stone-faced trappings of the second-wave. It’s a casual synonym ...