Is there a difference between a liver spot and a freckle?

Yes. Liver spot is the term commonly used to refer to a solar or senile lentigo. A lentigo is a hyperpigmented (usually brown or black) macule that is characterized histopathologically by increased numbers of melanocytes at the dermal– epidermal junction and increased amounts of melanin in both the melanocytes and basal keratinocytes. These lesions commonly arise on the dorsal aspects of the hands and face. Although solar lentigines are induced by ultraviolet radiation, they do not increase in pigmentation with exposure to the sun. Polymorphisms in the melanocortin receptor 1 gene (MCR1) have been associated with the development of freckles. Freckles (ephelides) are hyperpigmented macules limited to sun-exposed skin. Microscopically, they show increased amounts of melanin in basal keratinocytes, but not increased numbers of melanocytes. Freckles characteristically darken with sun exposure and lighten when the affected areas are protected from ultraviolet radiation.