1 [C,U] (formal 正式) a general idea not based on any particular real person, thing or situation 抽象概念

2 [U] (formal 正式) the state of thinking deeply about sth and not paying attention to what is around you 出神；心不在焉

3 [U] [C] (technical术语) the act of removing sth from sth else 提取；抽取: water abstraction from rivers 从河里抽水