An idiom is a group of words, or in other words, a phrase that has a meaning other than its literal meaning of the words in it.
Idiom:
look to (someone)
Meaning:
to depend on someone, to go to someone for help
Example:
My friend looks to his mother for help when he has a problem.
List of common idioms, their meanings and examples of their usage in sentences
An expression in the usage of a language that is peculiar to itself either in having a meaning that cannot be derived from the conjoined meanings of its elements or in its grammatically atypical use of words.