Short Answer 
Earth is the third planet from the Sun, known for supporting life and having liquid surface water, with oceans covering 71% of its surface. The term “Earth” originates from Old English and Germanic languages, unlike other planetary names rooted in Greco-Roman mythology, and misconceptions about the name “Terra” highlight the lack of a universal name for Earth across cultures.
1. Understand the Definition of Earth
The term Earth refers to the third planet from the Sun, uniquely known to support life. It is the only astronomical object recognized to have liquid surface water, which plays a crucial role in sustaining various ecosystems. Earth is primarily defined by its vast oceans, which cover approximately 71% of its surface, surpassing the size of lakes, rivers, and polar ice combined.
2. Explore the Etymology of “Earth”
The word “Earth” has its origins in Old English and Germanic languages, specifically referring to “ground” or “soil.” Unlike other planets in the solar system, which have names rooted in Greco-Roman mythology, Earth’s name stands out as the only one without such origins. This highlights the unique cultural and linguistic aspects associated with our understanding of Earth.
3. Clarify Misconceptions about Earth’s Name
It’s a common misconception that “Terra” serves as an international name for Earth; however, it is not recognized officially. English has become the predominant language in astronomy, but there is no universally accepted name for Earth across different cultures. Understanding this distinction is vital for comprehending how we communicate about our planet in a scientific context.