From Hull AWE
The adjective chronic is derived from the Greek word χρόνος (chronos), which means 'time'. It has one precise meaning, and a much more common colloquial set of meanings, which should be avoided in academic writing.
- In medical (and biological) terms, it means 'of long duration', 'long-lasting', 'lingering', or quasi-permanent. This has no direct link to the severity of the pain or condition to which it is applied: it states that the condition, or pain or similar, is on-going; may have only slow and gradual change; and has little sudden-ness about it. In medical terms, it is opposed to acute, which describes "a disease of rapid onset, severe symptoms, and brief duration" (Oxford's Concise Medical Dictionary).
- Colloquially, it developed, in the nineteenth century, from a figurative sense describing many long-lasting conditions such as war, revolutionary tendencies, or personal animosity, to
- the loose sense of 'very bad'.
It is this loose sense that should not be used in academic writing.
It is an error to use chronicle for any meaning to do with chronic.
It is a greater error to use the mis-spelling
chronicalfor any meaning.