Technical term in population genetics; refers to random changes in allele frequencies within a population, especially in small populations.
Genetic drift is a phenomenon in which gene frequencies change by chance.
Natural selection is a non-random process driven by fitness differences, while genetic drift is random and more pronounced in small populations.
Compound of 遺伝的 (genetic) + 浮遊 (drifting, floating). A calque of the English term 'genetic drift'.