This is the 875th most frequent Japanese word.
エネルギー
Energy.
エネルギー is used here to refer to natural energy emanating from the sun.
太陽のエネルギーは自然の源です。
The energy of the sun is the source of nature.
エネルギー refers to mental or emotional energy being devoted to a cause or activity.
彼女は子供の教育に全てのエネルギーを注いでいる。
She pours all her energy into educating children.
エネルギー is used as part of 'energy drinks,' referring to drinks that provide physical stamina and vitality.