• 貢献こうけん — contribution
• 進貢しんこう — presenting tribute (to a ruler/state)
• 年貢ねんぐ — annual tax; rice tax (traditional)
• 貢物みつぎもの — tribute; offering
• 貢ぐみつぐ — to offer; to support; to contribute

貢 is built around the idea of presenting something valuable. The 貝 part points to “valuable goods / money,” and the overall character came to mean **to offer tribute**, and more generally **to contribute**.