Here are some possibilities:
* Accompaniment: This is the most common noun and refers to something that accompanies something else. Example: "The pianist played the accompaniment for the singer."
* Company: This can mean a person or group of people who accompany someone. Example: "She enjoyed the company of her friends."
* Escort: This refers to someone who accompanies another person for protection or as a guide. Example: "The security guard acted as her escort."
* Attendant: This refers to someone who accompanies another person and assists them. Example: "The patient had an attendant to help her with her medications."
To give you the most accurate noun, please provide more context about how "accompany" is being used in the sentence.