那么 (nà me) is an adverb or conjunction meaning 'so', 'then', or 'that'—used to indicate consequence, degree, or contrast. It combines 那 (nà), meaning 'that', and 么 (me), a grammatical particle that softens or emphasizes the preceding word. Though written as two characters, it functions as a single unit and is never separated in speech or writing.

It commonly appears in cause-effect structures (e.g., 因为…那么…), comparisons (e.g., 那么高), or rhetorical questions (e.g., 那么怎么办？). Unlike English 'so', 那么 rarely begins a sentence on its own—it usually follows a clause or adjective to intensify meaning or introduce a logical next step. It’s neutral in register and widely used in both spoken and written Mandarin, especially in explanations, instructions, and everyday reasoning.