Gary L. answered 01/11/16
Tutor
New to Wyzant
The rank for professors at colleges and universities goes from lowest to highest: Lecturer, Assistant Professor, Associate Professor and finally Professor (sometimes called full Professor) and all of these ranks are all considered "professors". Professors are promoted through the ranks for various reasons, sometimes just work politics, other times for scholarly accomplishment or length of service. It should also be noted that a professor can be hired directly into any of these ranks based on their previous amount of experience or accomplishments in their field of instruction.
Adjust Professor - Adjuct in this case is just another word for "part-time" and while regular/full-time professors teach a full load of courses, as well as additional responsibilities, such as to participate in departmental and college governance meetings and committees, etc. while Adjust Professors usually only serve in the capacity of being limited to just the responsibility of teaching the one class that they instruct in and usually hold a full-time job (many times in the area they teach the 1-2 courses in) in addition to teaching this class.
Tenure is simply a status level that a professor reaches after a pre set number of years of service. A Tenured Professor is essentially a permanent appointment to their position with a little chance of dismissing them, but can be done in a process that cannot be done overnight and requires many times hearings, detailed justifications, etc. as opposed to simply "your fired". It should also be noted that tenure status can be reached by any of the mentioned professor ranks. So you can be a tenuered Assistant Professor or tenured Professor.
Additional information: Tenure is controversial to many as a unwarranted job security policy. However it should be noted that the concept of tenure is not to create a "cushy job" but in academia serves the purpose of protecting academic freedom by relieving professors from worry that they may be terminated for presenting a view point or discussion that a superior administrator disagrees or takes argument with. It's original purpose was to create an environment where free exchange of academic debate and thought can be expressed unburdened with restrictions due to worry of upseting someone else's opinion or beliefs that is in a position to terminate you.