I want to know why Objective-C is called "objective". (Other languages, such as C++ and Java are also object oriented, yet they don't carry the title "Objective".)
Simply because Objective-C is a superset of C, which adds object-oriented features (based on Smalltalk). The very first version was called "OOPC" for Object-Oriented Pre-Compiler, which was literally a precompiler for C which added objects and message-passing.