What is an organelle? What are some examples of an organelle?

As mentioned in your question, our bodies are made up of MANY organs, such as the heart, liver, lungs, and so on. The same is true of cells. Here are a few examples:

These are the components that make up a cell. They all work together to enable us to function. Think about it this way: if your heart stops working, you die. Likewise, if your cells start to fail, you would also pass away. This is why organelles are vital.

Cells come together to form tissues, which in turn form organs, organ systems become organelles, and tissues come together to form organs.

Thus, the term "cell organelle" refers to the subcellular components.

Here are a few instances:

The nucleus, mitochondria, endoplasmic reticulum, and chloroplasts are examples of specialized subunits within a cell that have specific functions. These subunits are known as organelles.