An organ is a distinct and specialized structure within a living organism that performs a specific function essential for the organism's survival or well-being. In animals, organs are typically comprised of different types of tissues working together; for example, the heart (which pumps blood), lungs (which facilitate breathing), and stomach (which aids in digestion) are all organs.
In plants, organs include structures like leaves, stems, and roots, each serving various roles vital for the plant's growth, nutrition, and reproduction. In a broader context, the term "organ" can also refer to any functional unit within a system, such as a musical organ, which is an instrument that produces sound.