奶奶 (nǎi nai) is a respectful and affectionate term for one's paternal grandmother — the mother of one’s father. Though both characters are written 奶, the second syllable is pronounced lightly, without tone (a neutral tone), making it distinct from the standalone word 奶 (nǎi), meaning 'milk' or 'nurse'. The repetition creates a kinship term following a common Chinese pattern for close family members (e.g., 爸爸, 妈妈). It reflects warmth and familiarity, typically used in direct address or when speaking about her within the family.

This term is specific to the father’s side; the maternal grandmother is called 姥姥 (lǎo lǎo) in most Mandarin-speaking regions. While 奶奶 can occasionally be used as a polite honorific for older women (especially in northern China), that usage is context-dependent and less common than its primary familial meaning. Children often use it early in language development, and adults continue using it throughout life to show respect and closeness.