* Concert: The prefix "con-" here means together or with. A concert is a musical performance where multiple musicians play together.
* Consonant: The prefix "con-" here means with or together. A consonant is a sound that is made by partially or completely stopping the flow of air from the mouth.
While the prefix is the same, the meaning is slightly different in each word. This is common with prefixes as their exact meaning can be influenced by the context of the word.