The word "a million" is often used to represent a large quantity or number. However, there are several synonyms that can be used in its place depending on the situation or context. For example, "a plethora" can be used to describe an excessive or abundant amount of something. "Countless" is another option, conveying the idea that the number is so vast that it cannot be accurately measured or counted. "Infinite" and "limitless" also express the idea of something that has no end or boundary. Lastly, "an ocean" can be used to describe an immense or boundless amount of something, such as people or ideas.