What does the term senescence mean?

1 : the state of being old : the process of becoming old. 2 : the growth phase in a plant or plant part (such as a leaf) from full maturity to death.

What is the full meaning of palliative?

A palliative is a drug or medical treatment that relieves suffering without treating the cause of the suffering. 2. countable noun. A palliative is an action that is intended to make the effects of a problem less severe but does not actually solve the problem. [formal]