The phrase "fundamental cornerstone" means something that is very important and essential to the foundation or basis of something. It is a crucial element that everything else relies on. Full definition
WHO and UNICEF consider that protecting, promoting and supporting breastfeeding are fundamental cornerstones for better health. (who.int)
Bloom believes that, no matter the country or the region, access to credit «is a fundamental cornerstone of social mobility» since it is the key for individuals to reach their economic goals.Bloom also pointed out the problem of governmental monopolies in credit checking. (bitcoinmining.shop)
Compassion for others is the fundamental cornerstone of Christian ethics; the Bible is the bedrock of the Christian faith. (religion.blogs.cnn.com)