The term 'reproductive part of a fungus' can be summarized by the word SPORE, which is a five-letter word. Spores are reproductive cells produced by fungi and other organisms that are capable of developing into a new individual without the need for fertilization. They are typically single-celled and are dispersed through the air or water to spread the organism's genetic material. Spores are also used by some plants as a form of asexual reproduction.