Learner's definition of DECISION
1 [count] : a choice that you make about something after thinking about it : the result of deciding
She announced her decision to go to medical school.
a big/controversial/final decision
Have you made/reached a decision?
After weeks of deliberation, he finally came to a decision. = After weeks of deliberation, he finally arrived at a decision.
He based his decision on facts, not emotions.
She made a conscious decision to leave the painting unfinished.
(Brit) The government has taken a decision to withdraw all troops. [=the government has made an important and official decision to withdraw all troops]
an informed decision [=a decision based on facts or information]
a split-second decision [=a decision that must be made in an instant]
◊ In informal spoken English, someone who says “Decisions, decisions” is having difficulty making a decision, usually about an unimportant matter.
2 [noncount], formal : the ability to make choices quickly and confidently
3 a : the particular end of a legal or official argument : a legal or official judgment
b : a report explaining why a legal or official judgment was made in a particular way
The U.S. Supreme Court's 1954 decision brought an end to racial segregation in public schools.
The Supreme Court handed down a 5–4 decision. [=five members of the court voted one way, and the other four members voted the opposite way, and the side with the five votes won]
The appeals court upheld the decision. [=the appeals court agreed with the decision made earlier by a lower court]
The appeals court overturned the decision. [=the appeals court disagreed with the decision made earlier by a lower court]
4 [noncount] : the act of deciding something