#rock
- Geological ablation — A conceptual form or terminological variant of 'ablație', used in classical geomorphology to describe the phenomenon of removal, washing away, or baring of rocks under the action of external agents (wind, flowing waters, waves). In soil dynamics, the term emphasizes the initial transport phase of fine detrital materials before they are deposited in sedimentary basins.
- Abu Simbel — A monumental archaeological complex located in Nubia, southern Egypt, consisting of two massive rock-cut temples carved during the reign of Pharaoh Ramesses II. Intended to celebrate the victory at Kadesh and to deify the royal couple, the complex is famous both for the four colossal statues of the pharaoh at the entrance and for a world-scale engineering operation in the 1960s, when it was entirely dismantled and relocated to save it from flooding caused by the construction of the Aswan High Dam.
- Acaena argentea — A species of creeping perennial plant within the Acaena genus, native to the temperate regions of South America (Chile and Argentina), remarkable for its exceptional ornamental value. It is individualized by its compound leaves, whose leaflets display metallic, silvery-blue reflections, covered in fine hairs that reflect sunlight and provide protection against dehydration in arid or alpine climates.
- Alpine plant — A plant structurally and physiologically adapted to live and grow at high altitudes, within the upper alpine zone or on rocky mountain ridges, displaying specific dwarf or pubescent traits.
- Actinite — A structural metamorphic rock or a variety of crystalline schist characterized by the predominant presence and radiating or fibrous arrangement of actinolite crystals (a mineral from the amphibole group). This technical term describes compact geological formations, created under medium temperature and pressure conditions, recognized for their greenish hues and specific acicular texture.
- Actophyte — A botanical term denoting a higher or lower plant that grows and develops exclusively on steep rocks, marine cliffs directly exposed to winds and waves, or in littoral zones with an extremely aggressive physical dynamics. This structural plant features a highly branched and resistant root or anchoring system.
- Aquifer — A porous or fractured underground geological formation (composed of sands, gravels, limestones, or sandstones) that is permeable, capable of storing and transmitting significant amounts of potable or industrial water, feeding springs and wells; as an adjective, it describes an earthen layer containing or conducting water. This underground structural reservoir plays a critical role in the hydrological cycle and securing the planet's water resources.
- Aquifuge — Water-repelling, impermeable; a compact geological stratum (such as dense clays, marls, or unfractured granites) that does not contain and does not allow the circulation or infiltration of water, acting as a natural insulating barrier; as an adjective, it also applies to technical materials treated for waterproofing. This structural element is essential in hydrogeology as it boundaries and protects underground aquifers.
- Aquitanian — The first geochronological stage or subdivision of the early Miocene epoch, situated at the base of the Neogene period, covering a time interval from around twenty million years ago; also, as an adjective, it describes geological elements from this stage or refers to the Aquitaine region in France and its historical inhabitants. This structural term marks a major transitional geological period, defined by global climatic shifts and significant tectonic movements.
- Adamellite — A coarse-grained plutonic igneous rock, considered a specific variety of granite or quartz monzonite, in which potassium feldspar and plagioclase feldspar (especially oligoclase or andesine) are present in approximately equal amounts. This crystalline rock also contains abundant quartz and ferromagnesian minerals such as biotite or hornblende, commonly found in ancient mountain massifs.
- Aerolitiform — Having the appearance, shape, structure, or chemical composition similar to that of an aerolite (stony meteorite); it refers specifically to mineral fragments, rocks, or terrestrial metallo-granular masses that exhibit textural characteristics similar to cosmic bodies that have crashed onto Earth.
- Aerolitic — Relating to aerolites, concerning aerolites (stony meteorites); originating from an aerolite or exhibiting compositional and structural characteristics specific to silicate rocks of extraterrestrial nature that have fallen to Earth.
- Boost-glider model — An experimental mockup or small-scale model of a hybrid aerospace vehicle, structurally designed to combine the aerodynamic characteristics of an aircraft (wings, gliding flight) with the reactive propulsion force specific to a rocket. This type of model is used in aeromodelling and rocketmodelling competitions to study dynamic behavior during vertical launch and controlled return phases.
- Aerospace — Belonging or relating simultaneously to Earth's atmosphere and the outer space beyond it, or to the design and construction of vehicles intended for navigation in both environments. This term describes an extremely complex industrial and scientific branch, structurally encompassing aerodynamic research, rocket engineering, satellite flight, and extra-atmospheric navigation systems.
- Aerozine — A storable, high-performance synthetic liquid fuel used in rocket and space module propulsion, composed of a 50:50 blend of hydrazine and unsymmetrical dimethylhydrazine (UDMH). This structural substance is hypergolic (ignites spontaneously upon contact with an oxidizer like dinitrogen tetroxide), being essential for orbital correction engines requiring multiple reliable restarts in a vacuum.
- Aethionema — A genus of annual or perennial herbaceous or subshrubby plants belonging to the Brassicaceae (Cruciferae) family, primarily native to the limestone and rocky regions of the Mediterranean basin and Asia Minor. These plants are structurally characterized by often fleshy, glaucous leaves, dense racemose inflorescences made of small decorative pink, purple, or white flowers, and uniquely flattened silicles, being frequently cultivated in alpine rock gardens across temperate zones.
- Aethionema diastrophis — Scientific name of a perennial stonecress species from the Aethionema genus, native to the mountainous and arid regions of Asia Minor, structurally characterized by stems woody at the base, compact glaucous leaves, and dense inflorescences with delicate intense pink flowers. The plant is of particular interest in phytogeography studies and is prized by collectors for its ability to colonize arid rocky crevices.
- Aethionema grandiflorum — Scientific name of the Persian stonecress, a perennial species from the Aethionema genus, native to the mountainous regions of the Caucasus, Iran, and Turkey, considered one of the most spectacular in the genus. It is structurally recognized by its bushy habit, slender stems, glaucous-blue leaves, and large, compact racemose inflorescences formed by numerous intense pink flowers, being widely used as an ornamental rock garden plant.
- Aethionema iberideum — Scientific name of a perennial dwarf stonecress species from the Aethionema genus, native to the rocky alpine zones of Greece, Albania, and Turkey. This plant is structurally characterized by short, trailing stems, small, oval, silvery or glaucous leaves, and dense inflorescences with white or pale pink flowers, resembling the genus Iberis in appearance, making it a highly appreciated niche species in rockeries.
- Aethionema pulchellum — Scientific name of a perennial dwarf stonecress species from the Aethionema genus, native to the calcareous mountainous regions of Turkey, Iran, and the Caucasus. This plant is structurally characterized by trailing or ascending stems, small glaucous-blue leaves, and dense, spherical inflorescences made of numerous delicate pink-purple flowers, being a species highly prized in rock garden landscaping due to its compact habit.