Smiles spread across their faces.
Meaning: This means that they were all very happy and enjoying themselves.
Choice of Words: Smiles are expressions of happiness or amusement. Spread means to move or distribute something over an area. Faces are the front parts of people's heads. When you put them together, it means that expressions of happiness or amusement moved or distributed over the front parts of their heads.
Alternative Expressions
Related Expressions