To have perseverance is to is to be steadfast and determined in the pursuit of a goal.
For instance, "The student showed perseverance in the pursuit of his academic career by working diligently at his studies and trying hard to make straight As." Perseverance can also indicate the continuation of effort or speech past any need, sometimes to the point of annoyance for the persons around them. This is different from the term "to perseverate" which indicates the continuation of speech or action after outside stimulation has ceased. Perseveration is a symptom in some psychological disorders such as schizophrenia and autism spectrum disorders.