جوهر essence
the basic or most important idea or quality of something

The essence of his argument was that education should continue throughout life
جوهر حجته هو أن التعليم يجب أن يستمر مدى الحياة

Yet change is the very essence of life
ومع ذلك فالتغيير هو جوهر الحياة

The essence of love is unselfishness
جوهر الحب هو الإيثار