Being awake means being conscious and alert, not asleep or dreaming. You can also say someone is awake at night if they're wide-awake, meaning unable to fall asleep.
When we talk about being awake, it usually means that our eyes are open and we're aware of what's going on around us. We use the word in a lot of different situations - like when we're getting up early for work or school, and someone says "good morning, I'm so glad you woke me up," meaning they're happy to be awake and start their day. We also talk about being awake during long drives or flights, where it's hard to stay alert and awake for a long time.
Not asleep; conscious.
