This is the 5518th most frequent Arabic word.
صفر
Zero; empty.
In this context, 'صفر' refers to the numerical value zero to describe the temperature.
درجة الحرارة اليوم صفر.
The temperature today is zero.
Here, 'صفر' metaphorically means starting from scratch or from the beginning.
سأبدأ من الصفر في تعلم الكمان.
I will start from scratch in learning the violin.
In this sentence, 'صفر' refers to the color yellow in dialectal Arabic.