In the right conditions, when solid particles meet liquid particles they can mix together to form a special mixture called a solution. This process is called dissolving. When they do dissolve, the solid part is called the solute and the liquid it dissolves in is called the solvent.
Here is a link that shows a video on dissolving solvents and solutes. http://www.northland.cc.mn.us/biology/BIOLOGY1111/animations/dissolve.html
"Like dissolves like" is an expression used by chemists to remember how some solvents work. It refers to "polar" and "nonpolar" solvents and solutes.