noun
degree of heat; temperature; enthusiasm
Used for both literal heat levels and figurative intensity of passion or interest. The enthusiasm sense is less common than 熱意 or 情熱.
この料理は熱度が足りないと美味しくならない。
This dish won't taste good if the heat isn't high enough.
彼の仕事に対する熱度は誰にも負けない。
His enthusiasm for work is second to none.
Compound of 熱 (heat) and 度 (degree). The figurative sense of 'enthusiasm' likely developed from the idea of measuring the intensity of passion.