They design and make new Software and contribute in their engineering. An engineer position would usually imply that you are a developer who has a specific type of degree, some knowledge of engineering, and is capable of designing a system.
Programmers write awesome code. Programmers does not develop or design or invent any thing new just use existed languages like C++, Java, python... and they are expert in those languages.
Coder is anyone who can write some code that compiles and runs, which will do something they want when its given the right inputs. This could be a program, a script, some classes or a library.
Developers are programmers to a greater or lesser extent. They are like programmers, but they are not expert like programmers and they perform general development and designing like web designers and developers.
High-level languages are really interesting if you think about it. They are essentially mid-level languages which just take the concepts of abstraction and high-level constructs to the extreme. For example, Java is mostly object-oriented, but it still relies on primitives which are represented directly in memory. Ruby on the other hand is completely object-oriented. It has no primitives (outside of the runtime implementation) and everything can be treated as an object.
Medium-level language (MLL) is a computer programming language that interacts with the abstraction layer of a computer system. Medium-level language serves as the bridge between the raw hardware and programming layer of a computer system. Medium-level language is also known as intermediate programming language and pseudo language.
Of all of the categories, it’s probably easiest to define what it means to be a low-level language. Machine code is low level because it runs directly on the processor. Low-level languages are appropriate for writing operating systems or firmware for micro-controllers. They can do just about anything with a little bit of work, but obviously you wouldn’t want to write the next major web framework in one of them (I can see it now, “Assembly on Rails”).