If you start counting from 1 and say one number every second, it would take you about 30 years to reach 1 billion (1,000,000,000). Long ago, the word billion meant a million million (that is, 1,000,000,000,000 or 12 zeros). This was the meaning used in countries like England and Germany. The word comes from “bi”, meaning two, because it was thought of as two “millions” written together: 1,000,000 1,000,000 making 1,000,000,000,000 (12 zeros). Later, Americans started using the word billion for a smaller number: 1,000,000,000 (9 zeros). Today, this 9-zero meaning is used almost everywhere in the world, especially in science and mathematics. The word billion itself is not very old. It became common only after the 1500s, and one early American use was recorded in 1729.