* Collection: This is the most common abstract noun, referring to the act of collecting or the group of things collected.
* Compilation: This refers to the process of gathering and organizing information or materials.
* Assembly: This is a more formal word for a group of people or things brought together.
* Accumulation: This emphasizes the gradual increase of something over time.
The best choice will depend on what you are trying to express. For example:
* "The collection of stamps was impressive."
* "The compilation of the report took several weeks."
* "The assembly of the team was successful."
* "The accumulation of wealth is a common goal."