The term 'sense of loss' can be summarized as a feeling of REGRET or sorrow. It is an emotional response to the absence of something or someone that was once present. This feeling can be caused by a variety of events, such as the death of a loved one, the end of a relationship, or the loss of a job. The term 'REGRET' is often used to describe this emotion, as it implies a sense of remorse or disappointment.