Picture a crowd of different things standing together, with one kind rising above the rest so that it is what you see first. That kind is the one that predominates — sometimes because there is simply more of it than of anything else, sometimes because it carries more weight than anything else there.
From the word’s history
Wiktionary records predominate as coming from Latin praedominor, and by surface analysis as pre- (over, in front) plus dominate. The literal picture, standing over the others, is the same picture the modern uses turn on.
Wiktionary 記 predominate 來自拉丁文 praedominor，拆開看就是 pre-（在上面、在前面）加 dominate（支配）。字面上的「壓在其他東西上面」，正好就是今天各種用法共用的那個畫面。
Wiktionary entry for predominate (kaikki:3f6f69a190036ae4:1285691914): From Latin praedominātus, past participle of praedominor. By surface analysis, pre- + dominate.
登入就可以看每一支怎麼連回核心畫面。