When someone has a life-threatening illness such as advanced cancer, thoughts about loss are common. For a patient these may be thoughts about loss of health, function, comfort or future life, while for a partner or relative it will be loss of the patient, and death and bereavement. The 'loss' is felt early, often at the time of diagnosis, so the practical and emotional consequences need to be dealt with early on. These issues of loss are important in palliative care. The focus of interest is understandably on the person who is ill, but sadly, there is often inadequate attention given to the needs of the key people who will be left behind. The chapter looks at the words that are used in the language around death – loss, grief, bereavement and mourning.