Simple Definition:
What is an element? An element is a substance (a type of material) made up of only one type of atom (a pure substance that cannot be broken down into simpler substances). There are 118 different elements that have been identified, each with its own unique properties and characteristics.
For example, gold is an element that is known for its shiny, yellow appearance and its ability to conduct (transfer) electricity. Oxygen is another element that is essential for life and is found in the air we breathe.
Very Simple Definition:
An element is a pure substance that cannot be broken down into simpler substances.