By name vs in name
 

What the difference between these two? I understand by name but in name I dont see it.

"In name" is used to name/designate someone or something, when the designation or name isn't a reality. "She is my mom, in name (but she is really my aunt/grandmother/etc.)."

"By name" is used when providing a real name/designation. "The young boy, Jack Ford by name, went hiking yesterday."

There are also cases when by name and in name are interchangeable. For example: He's my boss in name or by name only. This would mean the he is my supervisor, but basically I do what I do without his supervision.