Risk treatment is formally defined as the process of selection and implementation of measures to modify risk.
The things which can be done to 'modify' risk include:
take a risk reduction action - an action taken to lessen the likelihood, negative consequences or both, associated with a risk
risk avoidance - a decision not to become involved in, or to withdraw from, a risk situation
implementing a risk control - an existing process, policy, device, practice or other action that acts to minimise negative risk or enhance positive opportunities
risk sharing - sharing with another party the burden of loss, or benefit of gain from a particular risk.
Following all of these there is acceptance of the residual risk - the risk remaining after the implementation of risk treatment.
This set of risk treatment measures is also known as the four Ts: tolerate - do nothing, treat - do something (such as risk reduction or risk control), transfer - risk sharing, where the party you are sharing with takes it all, or terminate - do something different, risk avoidance.
There is also a fifth T: take the opportunity!