Greek language

Porphyrins (/ˈpɔːrfərɪns/ POR-fər-ins) are heterocyclic, macrocyclic, organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (=CH−). In vertebrates, an essential member of the porphyrin group is heme, which is a component of hemoproteins, whose functions include carrying oxygen in the bloodstream. In plants, an essential porphyrin derivative is chlorophyll, which is involved in light harvesting and electron transfer in photosynthesis.

The parent of porphyrins is porphine, a rare chemical compound of exclusively theoretical interest. Substituted porphines are called porphyrins. With a total of 26 π-electrons the porphyrin ring structure is a coordinated aromatic system. One result of the large conjugated system is that porphyrins absorb strongly in the visible region of the electromagnetic spectrum, i.e. they are deeply colored. The name "porphyrin" derives from Greek πορφύρα (porphyra) 'purple'.

The Siderian ( /saɪˈdɪəri.ən, sɪ-/) is the first geologic period in the Paleoproterozoic Era and Proterozoic Eon. It lasted from 2500 to 2300 million years ago (Ma), spanning a time of 200 million years, and is followed by the Rhyacian Period. Instead of being based on stratigraphy, these dates are defined chronometrically.

The name Siderian is derived from the Greek word sideros, meaning "iron", and refers to the banded iron formations formed during this period. The term was proposed by the Subcommission on Precambrian Stratigraphy as a subdivision of the Proterozoic Eon, and was ratified by the International Union of Geological Sciences in 1990. Since the Siderian is well-defined by the lower edge of iron-deposition layers and the initial appearance of glacial deposits, alternate names have been suggested to mark the upper half of the period stratigraphically. The term Oxygenian was suggested in 2012 due to the change in Earth’s atmosphere during this time, while the name Skourian was proposed in 2021 as a rock-based alternative. As of December 2024, the Siderian is the earliest internationally recognized period on the geological timescale.

Streptophyta (/strɛpˈtɒfɪtə, ˈstrɛptoʊfaɪtə/), informally the streptophytes (/ˈstrɛptəfaɪts/, from the Greek strepto 'twisted', for the morphology of the sperm of some members), is a clade of plants. The composition of the clade varies considerably between authors, but the definition employed here includes land plants and all green algae except the Chlorophyta and the more basal Prasinodermophyta.

The subphylum Hexapoda (from Greek for 'six legs') or hexapods comprises the largest clade of arthropods and includes most of the extant arthropod species. It includes the crown group class Insecta (true insects), as well as the much smaller clade Entognatha, which includes three classes of wingless arthropods that were once considered insects: Collembola (springtails), Protura (coneheads) and Diplura (two-pronged bristletails). The insects and springtails are very abundant and are some of the most important pollinators, basal consumers, scavengers/detritivores and micropredators in terrestrial environments.

Hexapods are named for their most distinctive feature: a three-part body plan with a consolidated thorax and three pairs of legs. Most other arthropods have more than three pairs of legs. Most recent studies have recovered Hexapoda as a subgroup of Pancrustacea.

Commentarii (Latin, Greek: hupomnemata) are notes to assist the memory, or memoranda. This original idea of the word gave rise to a variety of meanings: notes and abstracts of speeches for the assistance of orators; family memorials, the origin of many of the legends introduced into early Roman history from a desire to glorify a particular family; and diaries of events occurring in their own circle kept by private individuals. An example of this is the day-book drawn up for Trimalchio in Petronius's Satyricon (Satyricon, 53) by his actuarius, a slave to whom the duty was specially assigned. Other commentarii were memoirs of events in which they had taken part drawn up by public men. Examples of these are the Commentaries of Caesar: Commentarii de Bello Gallico on the Gallic Wars and Commentarii de Bello Civili on the civil wars; another example is that of Cicero on his consulship. Different departments of the imperial administration and certain high functionaries kept records, which were under the charge of an official known as a commentariis (cf. a secretis, ab epistulis). Municipal authorities also kept a register of their official acts.

The Commentarii Principis were the register of the official acts of the emperor. They contained the decisions, favourable or unfavourable, in regard to certain citizens; accusations brought before him or ordered by him; and lists of persons in receipt of special privileges. These must be distinguished from the commentarii diurni, a daily court-journal. At a later period records called ephemerides were kept by order of the emperor; these were much used by the collection of biographies known as Scriptores Historiae Augustae (see Augustan History). The Commentarii Senatus, only once mentioned (Tacitus, Annals, xv. 74) are probably identical with the Acta Senatus.

An artery (from Greek ἀρτηρία (artēríā)) is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in the pulmonary circulation that carry blood to the lungs for oxygenation, and the umbilical arteries in the fetal circulation that carry deoxygenated blood to the placenta. It consists of a multi-layered artery wall wrapped into a tube-shaped channel.

Arteries contrast with veins, which carry deoxygenated blood back towards the heart; or in the pulmonary and fetal circulations carry oxygenated blood to the lungs and fetus respectively.

Ancient Greek (Ἑλληνική, Hellēnikḗ [hellɛːnikɛ́ː]) includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (c. 1400–1200 BC), Dark Ages (c. 1200–800 BC), the Archaic or Homeric period (c. 800–500 BC), and the Classical period (c. 500–300 BC).

Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Epic and Classical periods of the language, which are the best-attested periods and considered most typical of Ancient Greek.

Tel Megiddo (from Hebrew: תל מגידו), Arabic: Tell el-Muteselim, is the site of the ancient city of Megiddo (/məˈɡɪdoʊ/; Hebrew: מגידו; Greek: Μεγιδδώ), the remains of which form a tell or archaeological mound, situated in northern Israel at the western edge of the Jezreel Valley. During the Bronze Age, Megiddo was an important Canaanite city-state, and in the Iron Age, it became a royal city in the Kingdom of Israel. The site is renowned for its historical, geographical, and theological significance, especially under its Greek name Armageddon, which is famously associated with the biblical Battle of Armageddon as described in the Book of Revelation.

Excavations have unearthed 20 strata of ruins since the Neolithic phase, indicating a long settlement period. Occupied continuously from the early Bronze Age (c. 3000 BCE) to the Persian period (c. 332 BCE), Megiddo was strategically located at the crossroads of major ancient trade routes, making it a key center for trade, politics, and military affairs. Excavations have uncovered impressive fortifications, including massive city walls and gates, as well as palaces, temples, residential buildings, and a sophisticated water system. The site is protected as Megiddo National Park and is a UNESCO World Heritage Site.

The Punic people, usually known as the Carthaginians (and sometimes as Western Phoenicians), were a Semitic people who migrated from Phoenicia to the Western Mediterranean during the Early Iron Age. In modern scholarship, the term Punic, the Latin equivalent of the Greek-derived term Phoenician, is exclusively used to refer to Phoenicians in the western Mediterranean, following the line of the Greek East and Latin West. The largest Punic settlement was Ancient Carthage, but there were 300 other settlements along the North African coast from Leptis Magna in modern Libya to Mogador in southern Morocco, as well as western Sicily, southern Sardinia, the southern and eastern coasts of the Iberian Peninsula, Malta, and Ibiza. Their language, Punic, was a variety of Phoenician, one of the Northwest Semitic languages originating in the Levant.

Literary sources report two moments of Tyrian settlements in the west, the first in the 12th century BC (the cities Utica, Lixus, and Gadir) that hasn't been confirmed by archaeology, and a second at the end of the 9th century BC, documented in written references in both east and west, which culminated in the foundation of colonies in northwest Africa (the cities Auza, Carthage, and Kition on the southern coast of Cyprus) and formed part of trading networks linked to Tyre, Arvad, Byblos, Berytus, Ekron, and Sidon in the Phoenician homeland. Although links with Phoenicia were retained throughout their history, they also developed close trading relations with other peoples of the western Mediterranean, such as Sicilians, Sardinians, Berbers, Greeks, and Iberians, and developed some cultural traits distinct from those of their Phoenician homeland. Some of these were shared by all western Phoenicians, while others were restricted to individual regions within the Punic sphere.

The Vettones (Greek: Ouettones) were an Iron Age pre-Roman people of the Iberian Peninsula.