2 or more tissues grouped together and performing specialized functions is called an organ.

Here's a breakdown:

* Tissue: A group of similar cells that work together to perform a specific function.

* Organ: A structure made up of two or more different tissues that work together to perform a complex function.

For example, the stomach is an organ made up of muscle tissue (for churning), epithelial tissue (for lining), connective tissue (for support), and nervous tissue (for coordination). Together, these tissues allow the stomach to break down food.