Yoga means to join or deep thought.The state in which you become one with the object of meditation signifies the real yoga. These days people associate yoga with the techniques which involve standing upside down and sweeping actions of arms and feet. This is yogasan and not yoga. These are methods of preparing the body for yoga. The asanas are required to make the body flexible and strong. Yogasana is the first step towards yoga.
Lord Krishna has defined Yoga (योगो भवति दुःखहा) as the destroyer of all the pains. Even AddyaGuru Shankaracharya has clarified Yoga as ("तां योगमितिमन्यन्ते स्थिरमिन्द्रिय धारणाम्")