* Lo: This is the masculine singular form of the definite article "the".
* único: This means "unique" or "only".
Here are some examples of how "lo único" is used:
* Lo único que me importa es tu felicidad. (The only thing that matters to me is your happiness.)
* Lo único que le falta a este plato es un poco de sal. (The only thing this dish is missing is a bit of salt.)
* Ella es lo único que me hace feliz. (She is the only thing that makes me happy.)
"Lo único" is often used to emphasize something as the singular most important thing or element in a situation.