A funnel is a tool used to guide liquids or fine-grained substances into containers with a small opening. It typically has a wide top that narrows down to a smaller spout, allowing for easy pouring without spills. Funnels are commonly made from materials like plastic, metal, or glass and are used in various settings, including kitchens and laboratories. In a business context, a funnel refers to the process of guiding potential customers through stages of engagement, from awareness to purchase. This concept, often called a sales funnel, helps businesses visualize and optimize their marketing strategies to convert leads into customers effectively.