The word "perpetual" has Anglo-Norman and Middle French roots, originating as early as the 12th century. Countless variations of the spelling of the word have existed in the past thousand years between these languages. Scholars derive classical Latin perpetī meaning "to put up with to the end" as a possible source of the modern-day word.
The word "perpetual" can refer to a condition, one in a never-ending state, or refer to a cycle, with potential to continue indefinitely. Regardless of the exact definition it always refers to something that will continue, a continuation. This continuation that characterizes the term perpetual is almost always measured in time. It is time that judges the value of the term perpetual in most cases.
To me, there seems to be two derivations of the definition for the term "perpetual". The first exists on a human scale. On a human scale, perpetual means something that will last until death. This derivation of the definition dates back to the 14th century. It can be used when describing a job or a position held for the rest of a person's life. A perpetual student, for example, is a person who maintains lifelong scholarly interests, and remains at university his whole life. The second derivation of the definition of perpetual also dates back to the fourteenth century. It describes a lasting condition on a universal scale, something that will last eternally. This can be used in the context of the perpetually expanding universe, for example.
The key distinction between these two interpretations of the same word is the level at which it can be observed. Something "perpetual" can be seen as a constant, never ending state. This state can either be cyclical or linear. If it is cyclical, it is most likely to belong to the human scale of the definition of perpetual, as long as the cycle can be observed at least once in a lifetime. A "perpetual rose", for example, follows a continuous flowering cycle several times a season. The word "perpetual" refers to the human scale in this case. Any perpetual cycle longer than a lifetime, such as the creation and destruction of stars, or any perpetual linear event that continues forever, such as the expansion of the universe, cannot be observed from start to finish. This kind or perpetual state exists on a universal scale.
A separate definition of "perpetual" also dates back to the 14th century and describes something that remains applicable for an indefinite period of time. This definition fits into both categories, as the uncertainty involved removes time as a measurement for the scale of the condition described as "perpetual".
To me there's something mystic about the word "perpetual" at the universal scale. It is something beyond us humans, something that cannot be contained or disrupted. To me, this mystical definition of "perpetual" should never be reduced to a human scale, because it loses its power. In my opinion, something truly perpetual cannot be fully experienced in a human's lifetime.