(1) SYN: transfer. (2) The conveyance of disease from one person to another. (3) The passage of a nerve impulse across an anatomic cleft, as in autonomic or central nervous system synapses and at neuromuscular junctions, by activation of a specific chemical mediator that stimulates or inhibits the structure across the synapse.neurohumoral transmission (4) In general, passage of energy through a material. [L. transmissio, a sending across]