Science

Continental Crust Definition Continental crust is the solid, outermost layer of the Earth, lying above the mantle.  This layer is sometimes called sial because its…

Basement Membrane Definition Basement membrane is a thin, delicate layer of connective tissue underlying the epithelium of many organs. It is also called basilemma. Basement…

Galena Definition Galena is a gray, metallic mineral occurring in cube-shaped crystals within veins of igneous rock or in sedimentary rocks. It is the main…

Metamorphism Definition Metamorphism is the process by which rocks are changed in composition, texture, or structure by extreme heat and pressure. The change occurs primarily…

Lymphatic Vessel Definition Lymphatic vessels are any of the vascular channels that transport lymph throughout the lymphatic system and freely anastomose with one another. It…

Absolute Value of an Integer The absolute value of an integer is the numerical value without regard to whether the sign is negative or positive.…

Silver Sulfide Definition Silver sulfide (Ag2S) is a dense black solid that is insoluble in all solvents, but is degraded by strong acids. It is…

Acanthite Definition Acanthite is one of the most important ores of silver with the chemical formula Ag2S. It is a stable and low-temperature form of…

Metasomatism Definition Metasomatism is the process by which the chemical composition of a rock is changed through the introduction or extraction of chemicals dissolved in…

Lymph Node Definition Lymph nodes (or Lymph gland) are small lumps of tissue that contain white blood cells, which fight infection. They filter lymph fluid,…

Pyrite Definition Pyrite (FeS2) is a silver to yellow, metallic, cubic mineral. Pyrite often crystallizes in cubes or octahedrons but also occurs as shapeless masses…

Mediastinum Definition Mediastinum is the area in the chest between the lungs that contains the heart, part of the windpipe (the trachea), the esophagus, and…