Why is the ninth month called September?
1560s, "to cause to multiply," from Latin propagatus, past participle of propagare "to set forward, extend, procreate" (see propagation). Intransitive sense "reproduce one's kind" is from c.1600. Related: Propagated; propagating.
propagate prop·a·gate (prŏp'ə-gāt')
v. prop·a·gat·ed, prop·a·gat·ing, prop·a·gates
To cause an organism to multiply or breed.
To breed offspring.
To transmit characteristics from one generation to another.
To cause to move in some direction or through a medium, such as a wave or a nerve impulse.