idiom
idiom (modismo)
a common phrase whose meaning is different from the meanings of its separate words.
Example
The trainer told a joke to break the ice. (Break the ice means to help people relax, not to crack ice.)
In Spanish
idiom (modismo) — una expresión común cuyo significado es distinto del significado de sus palabras por separado.
The trainer told a joke to break the ice. (Break the ice significa ayudar a la gente a relajarse, igual que «romper el hielo».)