"Preexisting conditions" refers to any health condition or illness that a person already has before getting health insurance coverage. It includes any medical condition that existed before the insurance policy began. Full definition
Some insurance companies used to refuse to cover kids with preexisting conditions such as asthma or diabetes. (whattoexpect.com)
Prior to January 1, 2014, when guaranteed issue of insurance coverage, elimination of preexisting condition exclusions, and several other critical ACA protections took effect for individual health insurance coverage, early retirees between ages 55 and 64 often faced difficulties obtaining insurance in the individual market because of age or chronic conditions that made coverage unaffordable or inaccessible. (cms.gov)
These typically include travel health insurance (coverage for medical emergencies such as a norovirus outbreak or prescription drugs for seasickness), an accidental death and dismemberment benefit, a waiver for preexisting conditions and medical evacuation. (valuepenguin.com)