The spreading abroad, or extension, of anything; diffusion; dissemination; as, the propagation of sound; the propagation of the gospel.

The spread of the action potential down an axon, caused by successive destabilizations of the neuronal membrane.

the spreading of something (a belief or practice) into new regions

more info The spreading of a fracture or crack within the snowpack.

Propagation, in the sense of a model at the same level of abstraction, "spreads" the effect of one or more parameters to other values according to its functional relationships.

increased or spread by natural reproduction.

Increase or spread by natural reproduction.

The process of reproduction either by natural or artificial means.

Refers to the form of transit of an action potential. It is self-regenerating throughout, at the same amplitude, and travels over long distances, e.g. motor and sensory axons. Speed is determined by diameter of the fibre.