RESISTANCE

Resistance is the opposition to current.  Resistance is measured in ohms. Examples of items with resistance are light bulbs, hair dryers, toasters, and little resistors in our lab kits.  

In a circuit drawing (called a schematic), resistors are represented with a symbol like this.

When electrons try to go through a resistor, they slow down.  Resistors in a circuit make the current be less by holding it back.  That is why it's called resistance.  You can think of a dam across a river as being resistance to the flow of water.  The water would be the current (moving electrons).