From what I can gather, terrestrial felicity which literally means ‘earth happiness’ is a reference to the Garden of Eden or some utopian system of life on earth. It also carries a connotation of more rural, natural, romantic or transcendental settings such as the untamed woods and a more primal, primitive or earlier, simpler time. So, it can refer to a place and/or a time; or even a general situation that defines a heaven on earth or the ideal living situation; on earth. Terrestrial felicity is to be differentiated from eternal felicity which is spiritual, metaphysical and most likely refers to an afterlife.
The Outer Banks is the place I’ve most gotten a sense of terrestrial felicity because of the landscape, atmosphere and its historically natural seashores.
My relationship with Becky was the closest I’ve ever come to terrestrial felicity with another person; it wouldn’t hurt if we lived on a tropical island.
Many anthropologists believe that if we are ever to achieve terrestrial felicity or even come close to a utopia, we must adopt a more social or altruistic philosophy to supplement the individualistic focus of capitalism.
The prime example of terrestrial felicity is the Garden of Eden; simple, natural, innocent and prior to corruption.