1. propagate sth (formal) means to spread an idea, a belief or a piece of information among many people: truyền bá (tư tưởng, niềm tin...)

Television advertising propagates a false image of the ideal family.

2. propagate sth also means to produce new plants from a parent plant. duy trì nòi giống, truyền giống, sinh sản

Propagation of red valerian

The plant can be propagated from seed.

Plants won't propagate in these conditions.