Error - A mistake or Getting unexpected output or Bug
Error, this term used to specify the Bug or inability of System to perform some intended thing.
Error can be either Syntactical or Logical.
When we fail to match the syntax(i.e. set of rules and regulations). It is easy to identify and and has low effect on system.
When we fail to match the expectation. It is occurred when we want to perform some things, but it will fail even though it is correct in syntax.
It is complex to trace. And can be worse effect on system/project.