-logy is a suffix in the English language, used with words originally adapted from Ancient Greek ending in -λογία (-logía). The earliest English examples were anglicizations of the French -logie, which was in turn inherited from the Latin -logia.The suffix became productive in English from the 18th century, allowing the formation of new terms with no Latin or Greek precedent.
The English suffix has two separate main senses, reflecting two sources of the -λογία suffix in Greek:
Eschatology (/ˌɛskəˈtɒlədʒi/ ; from Ancient Greek ἔσχατος (éskhatos) 'last' and -logy) concerns expectations of the end of present age, human history, or the world itself. The end of the world or end times is predicted by several world religions (both Abrahamic and Dharmic), which teach that negative world events will reach a climax. Belief that the end of the world is imminent is known as apocalypticism, and over time has been held both by members of mainstream religions and by doomsday cults. In the context of mysticism, the term refers metaphorically to the end of ordinary reality and to reunion with the divine. Many religions treat eschatology as a future event prophesied in sacred texts or in folklore, while other religions may have concepts of renewal or transformation after significant events.
The Abrahamic religions maintain a linear cosmology, with end-time scenarios containing themes of transformation and redemption. In Judaism, the term "end of days" makes reference to the Messianic Age and includes an in-gathering of the exiled Jewish diaspora, the coming of the Messiah, the resurrection of the righteous, and the world to come. Christianity depicts the end time as a period of tribulation that precedes the second coming of Christ, who will face the rise of the Antichrist along with his power structure and false prophets, and usher in the Kingdom of God. The explicit description of a new earth is primarily found in Christian teachings (this description can be found in Chapter 21 of the Book of Revelation). In later traditions of Islam, separate hadiths detail the Day of Judgment as preceded by the appearance of the Masīḥ ad-Dajjāl, and followed by the descending of ʿĪsā (Jesus), which shall triumph over the false Messiah or Antichrist; his defeat will lead to a sequence of events that will end with the sun rising from the west and the beginning of the Qiyāmah (Judgment Day).
In moral philosophy, deontological ethics or deontology (from Ancient Greek δέον (déon) 'duty, obligation' and -λογία (-logía) 'study of') is the normative ethical theory that the morality of an action should be based on whether that action itself is right or wrong under a series of rules and principles, rather than based on the consequences of the action. It is sometimes described as duty-, obligation-, or rule-based ethics. Deontological ethics is commonly contrasted to utilitarianism and other consequentialist theories, virtue ethics, and pragmatic ethics. In the deontological approach, the inherent rightfulness of actions is considered more important than their consequences.
The term deontological was first used to describe the current, specialised definition by C. D. Broad in his 1930 book, Five Types of Ethical Theory. Older usage of the term goes back to Jeremy Bentham, who coined it prior to 1816 as a synonym of dicastic or censorial ethics (i.e., ethics based on judgement). The more general sense of the word is retained in French, especially in the term code de déontologie (ethical code), in the context of professional ethics.
Physiology (/ˌfɪziˈɒlədʒi/; from Ancient Greek φύσις (phúsis) 'nature, origin' and -λογία (-logía) 'study of') is the scientific study of functions and mechanisms in a living system. As a subdiscipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out chemical and physical functions in a living system. According to the classes of organisms, the field can be divided into medical physiology, animal physiology, plant physiology, cell physiology, and comparative physiology.
Central to physiological functioning are biophysical and biochemical processes, homeostatic control mechanisms, and communication between cells. Physiological state is the condition of normal function. In contrast, pathological state refers to abnormal conditions, including human diseases.
Ecology (from Ancient Greek οἶκος (oîkos) 'house' and -λογία (-logía) 'study of') is the natural science of the relationships among living organisms and their environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere levels. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history.
Ecology is a branch of biology, and is the study of abundance, biomass, and distribution of organisms in the context of the environment. It encompasses life processes, interactions, and adaptations; movement of materials and energy through living communities; successional development of ecosystems; cooperation, competition, and predation within and between species; and patterns of biodiversity and its effect on ecosystem processes.
Geology is a branch of natural science concerned with the Earth and other astronomical bodies, the rocks of which they are composed, and the processes by which they change over time. The name comes from Ancient Greek γῆ (gê) 'earth' and λoγία (-logía) 'study of, discourse'. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with Earth system science and planetary science.
Geology describes the structure of the Earth on and beneath its surface and the processes that have shaped that structure. Geologists study the mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at a given location; geochemistry (a branch of geology) determines their absolute ages. By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. One aspect is to demonstrate the age of the Earth. Geology provides evidence for plate tectonics, the evolutionary history of life, and the Earth's past climates.
Hydrology (from Ancient Greek ὕδωρ (húdōr) 'water' and -λογία (-logía) 'study of') is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydrologist. Hydrologists are scientists studying earth or environmental science, civil or environmental engineering, and physical geography. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as environmental preservation, natural disasters, and water management.
Hydrology subdivides into surface water hydrology, groundwater hydrology (hydrogeology), and marine hydrology. Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology, drainage-basin management, and water quality.