What is the difference between 'mostly' and 'mainly'?

The Words "mostly" and "mainly" are often used interchangeably, but they can have slightly different connotations. "Mostly" typically refers to the larger part or majority of something, emphasizing quantity or prevalence. In contrast, "mainly" often highlights the primary or most significant aspect among several options, focusing more on importance than on quantity. In many contexts, either Word can suffice, but subtle distinctions may apply depending on the situation.