In terms of geography, seas are smaller than oceans and are usually located where the land and ocean meet. Typically, seas are partially enclosed by land. Seas are found on the margins of the ocean and are partially enclosed by land. Here, you can see that the Bering Sea is part of the Pacific Ocean.

In geographical terms, the primary differences between a sea and an ocean are scale, location, and degree of enclosure by land. Oceans are the largest bodies of saltwater on Earth, covering approximately 71% of the planet's surface and defined by vast, open expanses like the Pacific or Atlantic. Seas, conversely, are smaller subdivisions of these oceans and are typically located where the ocean meets the land. Most seas are partially enclosed by land masses; for example, the Mediterranean Sea is almost entirely surrounded by Europe, Africa, and Asia, while the Caribbean Sea is bordered by the Americas and the Antilles. A rare exception is the Sargasso Sea, which is defined not by land but by ocean currents. While the terms are often used interchangeably in casual conversation, a sea is nearly always found on the margins of an ocean. Furthermore, because seas are closer to land, they often exhibit different levels of salinity, temperature, and marine biodiversity compared to the deep, open waters of the central oceans.