Storge is the Greek term for familial affection discussed by C.S. Lewis in The Four Loves.
In the book, Lewis examines four traditional Greek words associated with different forms of love: storge, philia, eros, and agape. He uses storge for affectionate natural love, especially the bond associated with family members and familiar relationships.
The distinctions are useful but should not be treated as a rigid scientific classification of every human relationship. Lewis was writing a philosophical and theological work in an accessible literary style, drawing on classical vocabulary to explore ordinary experience. His treatment also connects the four loves with Christian ideas about divine love.
The other Greek terms have different emphases in Lewis’s discussion. Philia concerns friendship, eros refers to romantic or sexual love, and agape describes gift-like or charitable love. Transliteration can vary, so storge may also appear as storgē in scholarly writing.