eta e·ta (ā'tə, ē'tə)
Symbol η The seventh letter of the Greek alphabet.
The symbol for Planck's constant..
The symbol for the element hydrogen.
The lightest and most abundant element in the universe, normally consisting of one proton and one electron. It occurs in water in combination with oxygen, in most organic compounds, and in small amounts in the atmosphere as a gaseous mixture of its three isotopes (protium, deuterium, and tritium) in the colorless, odorless compound H2. Hydrogen atoms are relatively electropositive and form hydrogen bonds with electronegative atoms. In the Sun and other stars, the conversion of hydrogen into helium by nuclear fusion produces heat and light. Hydrogen is used to make rocket fuel, synthetic ammonia, and methanol, to hydrogenate fats and oils, and to refine petroleum. The development of physical theories of electron orbitals in hydrogen was important in the development of quantum mechanics. Atomic number 1; atomic weight 1.00794; melting point -259.14°C; boiling point -252.8°C; density at 0°C 0.08987 gram per liter; valence 1. See Periodic Table. See Note at oxygen.
Heroin (Narcotics)Related Terms
1. A simple markup language intended for quick conversion of existing text to hypertext.
2. A method of marking common words to call attention to the fact that they are being used in a nonstandard, ironic, or humorous way. Originated in the fannish catchphrase "Bheer is the One True Ghod!" from decades ago. H-infix marking of "Ghod" and other words spread into the 1960s counterculture via underground comix, and into early hackerdom either from the counterculture or from SF fandom (the three overlapped heavily at the time). More recently, the h infix has become an expected feature of benchmark names (Dhrystone, Rhealstone, etc.); this follows on from the original Whetstone (the name of a laboratory) but may have been influenced by the fannish/counterculture h infix.