What is custom?
The models of the external human activities.
The norms that belong to specific tribes, ethnics or groups of people.
The relationship between law and custom
Law follows some specific customs such as commercial custom, just
custom etc.
Custom is a part of law in some countries. (Common Law System)
Thai law has accepted the application of local custom in order to
fill the gap of law (Section 4 of C.C.C.)