Three economists go in to interview for a job at the AEA meetings. One is an econometrician, the other a macro economist, and the third is a labor economist.
The interviewers ask each one of them to describe their field of study.
In her interview, the econometrician states "Econometrics is study of the finite sample and asymptotic properties of estimators with particular relevance for economic research"
After the econometrician leaves, the macro economist enters the interview room and after being asked the interview question states "Macroeconomics studies the aggregation of markets, with particular focus on general equilibrium and national level policy instruments such as fiscal and monetary policy."
The labor economist knocks on the door and enters the hotel room after the macroeconomist leaves. When asked the same question of defining their field of study, they ask rhetorically "what is labor economics??" They pause. After a minute, they stand up, go over to the window blinds, and close them. They walk back and sit down. They slowly lean forward and whisper to the interviewer "What do you want it to be?"
In all seriousness there are a lot of fields that are tweeners that could be labor, could be public, could be law and econ. Take for instance crime. Based on Becker's model, crime is a labor supply choice. However, enforcement is a local public good problem, and sanctions and courts are part of of law and economics. So there are a ton of things that go into labor supply choices given that labor, leisure, and consumption are the fundamental choices we make every day of our lives.