The term evolved over time. "Per" was often abbreviated to "p", and "cento" was contracted until it eventually became the modern symbol: %.
The term is conceptually identical to one "cent" being 11001 over 100 end-fraction of a dollar, thus 37 cents is 37 percent of a dollar. Deep Mathematical Meaning per centum
"Percent" (one word) is standard American English, while "per cent" (two words) is more common in British English. How to Pronounce Percent - Deep English The term evolved over time
