Nowadays it has come to mean 'any kind of yoga that is gentle and the teacher talks in a calm, serene voice that makes me feel peaceful.'
Look around and you'll see: the world has gone yoga mad. There is ashtanga yoga, for young fit twenty somethings, with boundless energy and flexi-bodies. There is hot yoga, for people who have circulatory problems and think they need to turn the heater up to 40 degrees and close all the windows.
There is laughing yoga, pregnancy yoga, mums and bubs yoga, chanting yoga, chakra yoga, Dru yoga and any number of 'styles' that people have made up.
So how do you know which yoga to choose? Find the style that suits you. Experiment with lots of different classes and teachers, and find what works. That means, you feel better after class than before. Your body recovers from injuries, and doesn't get injuries from classes. You head space improves, and life becomes a little less of a challenge.
So, what kind of yoga do you do? And does it matter what it's called, as long as it works?