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.
jockey for position
to try to push one's way into an advantageous position
Several of the salesmen began to jockey for position when they learned that the director of sales was leaving.
List of common idioms, their meanings and examples of their usage in sentences
A group of words which have a different meaning when used together from the one they would have if you took the meaning of each word separately.