After recognizing the Antarctic Ocean the National Geographic Society in June 2021, there are 5 main giant and large oceans in the Earth. They are Pacific, Atlantic, Indian, Antarctic/Southern, And Indian. Some counted it 7 by dividing the Pacific, and Atlantic into south and north. Some calculated this number as 8 with adding indian ocean

To understand this we first need to know about supercontinents. A supercontinent is a large continent that unites all of Earth's continental block or craton (a giant area held above a tectonic plate) or multiple cratons.These tectonic plates move very slowly. But, this movement can create a large difference in millions of years. Moving these tectonic plates creates or breaks supercontinent or continents and oceans divided.

The last supercontinent was Pangea (299-195 mya). When there was only one Ocean called 'Panthalassa'. The cratons of Pangea were fixed in one place for millions of years. due to this difference in energy and pressure of every craton, the water under it took another different behavior, weather color, etc. Later, due to the movement of tectonic plates, these cratons moved and took the shape of the present earth, and then different types of oceans were formed next to different continents based on gas, color, temperature, chemicals, and climates.

The Oceans are different based on their colors, behavior, gases, formation, ages, chemicals, climates, salinity, alkalinity, tides, etc.