What word or phrase does your mother always say?
1650s, from French didactique, from Greek didaktikos "apt at teaching," from didaktos "taught," past participle of didaskein "teach," from PIE root *dens- "wisdom, to teach, learn." Related: Didactically; didacticism.
didactic di·dac·tic (dī-dāk'tĭk)
Of or relating to medical teaching by lectures or textbooks as distinguished from clinical demonstration with patients.