Bug Vs Error Vs Defects ?

Bug:- 

1. A software bug may be defined as a coding error that cause an unexpected defect,fault or flow.In other words if a program does not perform as intend  it is most likely a bug.
2. If that error comes at the tome of development stage before production then it is bug. 
3. A fault in a program which cause the program to perform in an unintended or unanticipated manner.  

Error:- 

1. A mismatch between the program and its specification is an error in the program.
2. The difference between expected results and actual results is error.
3. A mistake in program called error.

Defect:- 

1. Defects is the variance form a desired product attribute it can be two types.
2. Defects from the products or a variance form customer/user expectation it is a flow in the software system and has no impact until it affects the user/customer and operational system 90% of all defects can be caused by process problem.
3. If that error comes after production then we say it is defect.
4. It ts a mismatch between the requirements.It is found in last stage of production.