A "howler" typically refers to a type of monkey known as the howler monkey. These monkeys are famous for their loud vocalizations, which can be heard over long distances in the rainforest. They use their calls to communicate with each other, especially to mark territory and attract mates. In a broader context, the term "howler" can also describe a mistake or blunder, often in a humorous way. For example, a "howler" in a speech or writing might be a glaring error that stands out and elicits laughter or surprise from the audience.