Continents  /ˈkɒntɪnənts/  

Plural noun

Synonyms: Lands, mainlands, continentals, boundaries

Hindi: महाद्वीपों
Punjabi: ਮਹਾਂਦੀਪ

Meaning:

Continents is a plural noun for a word "Continent."

Continents: any of the world's main continuous expanses of land (Europe, Asia, Africa, North and South America, Australia, Antarctica).

Sentence:
A simple, practical boundary between the three oceans can be obtained by prolonging the meridian of the southern extremity of each of the three southern continents to the Antarctic circle.