There isn't an organelle that holds the nucleus together. The nucleus itself is a membrane-bound organelle that contains the cell's genetic material (DNA).

Here's how the nucleus is held together:

* Nuclear Envelope: This double membrane surrounds the nucleus and separates its contents from the cytoplasm. It has pores that allow for the passage of molecules in and out of the nucleus.

* Nuclear Lamina: This mesh-like network of protein filaments lines the inner surface of the nuclear envelope. It provides structural support to the nucleus, maintaining its shape and anchoring the chromosomes.

* Chromatin: The DNA within the nucleus is organized into chromatin, a complex of DNA and proteins. This structure helps to package and organize the DNA, making it more manageable and accessible.

So, it's not a single organelle, but rather a combination of structures that work together to hold the nucleus together.