What is the difference between tissue engineering and 3D bioprinting?
Tissue engineering is research into ways of organizing cells and cell droplet/matrix structures into a useful form, usually for medical applications. In the near future, tissue engineering could refer to rewriting or genetically modifying cells for a new purpose or to enhance their existing function. Even more into the future and tissue engineering could mean custom-building multi-cell structures from scratch on a computer.

3D bioprinting is the practical or laboratory deployment of the first technology mentioned above - a subset of tissue engineering.

In a nutshell:

Tissue engineering = "Come up with a creative way to arrange these cells and cell structures into something useful".

3D bioprinting = "Use the above-mentioned technology to build part of a synthetic organ".