What do graduate students generally call postdocs in the same group? Call senior, senior, teacher, or. . Brother?

You can decide the name of a postdoctoral fellow according to his actual age, pre-school status and occupation. If the age gap is large, it should be called according to the actual generation. If the age difference is within 10 years old, you can generally call your brother or elder brother. Before going to school, he was a leader, and his address should be different from that of people of the same age. In addition, he was a teacher before going to school. He can be called a teacher or an engineer. In short, the specific address should be suitable for his identity and meet his psychological expectations.