An organoid is a miniaturised and simplified version of an organ produced in vitro in three dimensions that mimics the key functional, structural, and biological complexity of that organ.[1] It is derived from one or a few cells from a tissue, embryonic stem cells, or induced pluripotent stem cells, which can self-organize in three-dimensional culture owing to their self-renewal and differentiation capacities. The technique for growing organoids has rapidly improved since the early 2010s, and The Scientist named it one of the biggest scientific advancements of 2013.[2] Scientists and engineers use organoids to study development and disease in the laboratory, for drug discovery and development in industry,[3] personalized diagnostics and medicine, gene and cell therapies, tissue engineering, and regenerative medicine.