Scientifically there is no difference, with both words being interchangeable for columbiformes. Ornithilogically, 'dove' is often assigned to smaller, lighter bodied species, and 'pigeon' to heavier bodied ones, but this is not consistent (ie. rock dove). Culturally, "pigeon" tends to be more derogatory. Many will call white homing pigeons 'doves', and often genuinely mistake them as being a different species from what they consider to be 'pigeons'. Victoria crowned pigeons and such tend to be outside of the general public's awareness.