Chronic
Etymology
From Greek chronikos, "of time," from chronos, "time" (the same root as "chronicle" and "chronology"). The core idea is duration. Medicine uses it for conditions defined by how long they last — months or years — as opposed to sudden, short ones. In everyday speech it stretches to any persistent problem, as in "chronic lateness."
adjective · /KRON-ik/
Persisting over a long time or recurring again and again, rather than passing quickly.
What it names
The difference between an illness you get over and one you have to live with and manage — a distinction that shapes daily life.
Example
Managing chronic back pain became less about a cure and more about small daily adjustments.
Related idea
Acute is its opposite — sudden and short-lived rather than long and lingering.