Experiential means based on experience, or to do with experience: what you have lived, tried, felt, or done yourself, not only what you have read or been told. Teachers often say experiential learning — you learn by doing, making, going, tasting, not only by sitting still with a book. It is a formal school-and-university word. You will not hear it much in daily chat. Though actually, people mix it up with experimental, which is about tests and trying a new method, often in a lab or a new project. Experiential is about experience. Experimental is about experiment. The two sit near each other, but they do not do the same job.