The word "决定" is formed by combining the characters "决" and "定". "决" originates from the water radical (氵) and the component "夬", which historically implied breaching or deciding, conveying a sense of resolution. "定" combines the roof radical (宀) with "正", indicating stability or settlement. Together, they create a compound where "决" contributes the notion of determination and "定" adds the idea of conclusiveness, resulting in the meaning "to decide".