“Condition” is the term used by most insurance companies to refer to an injury or an illness.
Most policies will have their own definition which you will find in their policy document.
Here are a couple of examples.
John Lewis
“A specifically identifiable illness, disease, injury, accident or any change in your pet’s normal health state, its bodily functions, or behaviour. If a vet considers a number of injuries, accidents, illnesses or changes in your pets health or behaviour connected they will be considered to be one incident”
Animal Friends
“Condition means any injury sustained during, or resulting from, a single accident or any manifestation of illness having the same diagnostic classification or resulting from the same disease process regardless of the number of incidents or areas of your pet’s body affected.”
Related and Bilateral Conditions
Most pet insurance companies will exclude from your policy not only conditions which existed prior to taking out the policy (pre-existing conditions), but also any conditions which are related to them. This can be contentious as in reality it can be almost impossible to prove whether conditions are related.
Bilateral conditions are generally also excluded. So for example if your pet had an ear problem before taking out the policy you are likely to find that the condition will be excluded for both ears.