existence
英 [ɪɡˈzɪstəns]   美 [ɪɡˈzɪstəns]  
n.
存在;实有;(尤指艰难或无聊的)生活，生活方式

例句

I was unaware of his existence until today.

直到今天我才知道有他这么个人。

We led a poor but happy enough existence as children.

我们儿时的生活虽然贫穷却过得很愉快。