The term "less than" is used in mathematics and everyday language to indicate that one quantity is smaller than another. For example, if you have 3 apples and your friend has 5 apples, you can say that 3 is less than 5. This concept is often represented by the symbol "<", so you would write 3 < 5. In addition to numbers, "less than" can apply to various comparisons, such as weight, height, or age. For instance, if a dog weighs 20 pounds and a cat weighs 10 pounds, you can say the cat's weight is less than the dog's weight, or 10 < 20.