jarð
Jarð is a nominal stem in Icelandic used to form terms related to the earth, ground, or soil. In contrast, the standalone noun for “earth” is jörð. The form jarð appears in a wide range of technical terms and compounds, such as jarðskorpa (Earth’s crust), jarðhiti (geothermal heat), jarðvegur (soil), jarðefni (minerals or earth materials), jarðlög (strata), and jarðfræði (geology). Through these compounds, jarð conveys the sense of the natural earth and related processes rather than a specific, definite object.
Etymology: jarð derives from the Old Norse jǫrð, from Proto-Germanic *erþō, cognate with English earth, German
Usage notes: In everyday language, speakers typically use jörð for the planet or soil, while jarð- appears