[countable] a choice or judgement that you make after thinking and talking about what is the best thing to do. I think I've made the right decision. Decision-maker · Split decision · The Miranda decision

a choice or judgment that you make after thinking and talking about what is the best thing to do to make a decision (= to decide)

There are ten meanings listed in OED's entry for the noun decision, two of which are labelled obsolete. See 'Meaning & use' for definitions, usage, ...

the process of deciding about something important, especially in a group of people or in an organization responsibility for decision-making All the staff ...

​the process of deciding about something important, especially in a group of people or in an organization. responsibility for decision-making ...

There are two meanings listed in OED's entry for the verb decision. See 'Meaning & use' for definitions, usage, and quotation evidence.

a choice that you make about something after thinking about several possibilities: make a decision She has had to make some very difficult decisions.

​[transitive, intransitive] (law) to make an official or legal judgement. decide something The case will be decided by a jury.

​a person who makes important decisions. Mary is the decision-maker in the house. the role of retailers as decision-makers. Topics Preferences and decisions ...

​a decision made at a high level in an organization. The closing of the sports centre was an executive decision and it's wrong to criticize the local ...