Anything littoral has to do with a coast or shore. A littoral state has a coast, so Florida, California, and North Carolina are littoral states, to name a few.
If you live far away from any water, then you probably won't hear the word littoral much because it refers to things related to shores and coasts. A house overlooking the ocean is littoral. A business is littoral if it sells things to people hanging out on the beach. You can also use littoral as a noun to mean the area near a coast or shore — if you grew up near the water, you grew up in a littoral.