The term “emanationism” is employed in a Buddhist context by Seyfort Ruegg (The Buddha’s Nirvāna, p. 263). According to a Wikipedia article (accessed on 1.4.2013) “emanationism” is said to be “an idea in the cosmology or cosmogony of certain religious or philosophical systems. Emanation, from the Latin emanare meaning ‘to flow from’ or ‘to pour forth or out of,’ is the mode by which all things are derived from the First Reality, or Principle. All things are derived from the first reality or perfect God by steps of degradation to lesser degrees of the first reality or God, and at every step the emanating beings are less pure, less perfect, less divine. Emanationism is a transcendent principle from which everything is derived, and is opposed to both Creationism (wherein the universe is created by a sentient God who is separate from creation) and materialism (which posits no underlying subjective and/or ontological nature behind phenomena being immanent).”
It seems we can borrow the term “emanationism” to express a Buddhist philosophical idea—more in connection with Buddhology rather than with Buddhist cosmology or cosmogony—that the Buddha or a buddha “emanates” or “manifests” in the world for which there are many models (proposed or presupposed by different Buddhist traditions or systems), such as the sun-rays (or “automatism”) model of the Ratnagotravibhāga (I am thinking of the lines therein beginning with chos kyi sku las ma g.yos par || sprul ba’i rang bzhin sna tshogs kyis ||).
A point to note is dharmakāya is said to be for svārtha and rūpakāya for parārtha; dharmakāya is inaccessible for sentient beings, who are not buddhas (i.e. gdul bya rang rgyud pa). Of the two kinds of rūpakāya, saṃbhogakāya/sāṃbhogikakāya (longs spyod rdzogs pa’i sku) are said to be accessible only to pure vineyas (i.e. bodhisattvas of the 8–10th bhūmis or dag sa gsum). On the contrary, nirmāṇakāya/nairmāṇikakāya (sprul pa’i sku) is said to be accessible to all pure and impure vineyas. Some Tibetan sources speak of phye sprul longs sku, that is, a kind of half saṃbhogakāya and half nirmāṇakāya, which are accessible also to bodhisattvas of seven impure stages (ma dag sa bdun).
Interesting is the subcategories of nirmāṇakāya/nairmāṇikakāya. While the so-called mchog gi sprul pa’i sku must necessarily be like the Śākyamuni Buddha, so to speak, a “formal” or “official” buddha, who manifests the twelve great deeds (mdzad pa bcu gnyis), other kinds of nirmāṇakāya would have no fixed forms. The idea here is that a buddha can appear in any form such as in the forms of animate beings (even as hunters and prostitutes) and as inanimate objects (even as islands and bridges). The bottom-line is the beneficence. (This should, by the way, remind believing Buddhists to watch out whom they lookdown on, disparage, or pass categorical judgments on. To be safe, better try to treat everyone and everything with respect.)
Now there is also a notion that everything or everyone is an emanation of something or someone. Consider the five kinds of sprul pa, such as nyon mongs pa’i skrul pa. Explore this concept!
One does come across a cosmology/cosmogony-related emanationism. According to the two Buddhist versions of “idealism” (i.e. phyi don med pa’i sems tsam and byed pa po gzhan med pa’i sems tsam), the entire habitats (snod) and inhabitants (bcud)—i.e. bhājanaloka and sattvaloka—are the mere self-projections of mind (sems: citta). According to the rDzogs-chen and other similar systems, the myriad world of appearances emanates or emerges or manifests from the metaphysical ground (gzhi), which is groundless-and- rootless (gzhi med rtsa bral).