True seals are marine mammals that are known for their streamlined bodies and smooth, sleek surfaces. They are also called earless seals, as they lack external ears. There are several synonyms for the term 'true seal,' including phocid, pinniped, and earless seal. These synonyms are often used interchangeably in the scientific literature and among experts in the field. Additionally, true seals are frequently compared to their close relatives, such as walruses and sea lions, which possess additional features such as tusks and external ears, respectively. Nevertheless, true seals remain distinct in their own right and are vital members of ocean ecosystems worldwide.