What beverage type is indicated by the letter "M"?

The beverage type indicated by the letter "M" is espresso macchiato. This beverage is characterized by its unique preparation, which involves pulling a shot of espresso and then adding a small amount of frothed milk. The term "macchiato" translates to "stained" or "spotted" in Italian, reflecting the way the frothed milk is used to 'stain' the espresso rather than dominate its flavor.

Espresso macchiato is distinct from other milk-based drinks in that it focuses primarily on the espresso, allowing for the bold flavor of the coffee to remain predominant while the milk simply adds a touch of creaminess. This is in contrast to beverages like lattes and steamers, which typically have a higher milk-to-coffee ratio, resulting in a less intense coffee flavor.

Given the context of this question, the reference to the letter "M" aligns with "macchiato," establishing a clear connection while demonstrating an understanding of how different types of coffee beverages are categorized based on their ingredients and preparation methods.