reactivity - the state or power of being reactive or the degree to which a thing is reactive.
Empathy is often defined as the feelings and actions that come up in response to what some else shares, their feelings and situation. For example, you see a homeless person, some people define empathy as the sadness, anxiety, stress, anger, pity, sympathy, concern, etc. etc. that come up in you.
These reactions will come up, but empathy is maintaining and staying present with the person.. all this may come up in the background,
In the Empathy Circle: While we are listening we just met the speaker with empathic presence. The various reactions may be going on in us but we set them aside and don't let them take over the space. When it is our turn to speak, we can fully share them and they will be met with empathy by the listener.
Split awareness; we can be having a high degree of presence with the speaker. There are a lot of other feelings arising in awareness as they speak, but the feelings and thoughts are let go, set aside, tabled, etc., for the time being.
Identifying: This also overlaps with identifying with the person. The homeless person is a veteran, and I'm a veteran, I have something in common with them. I start thinking of my experiences.