1. hydrogen-a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe. atomic number 1, H. tritium-a radioactive isotope of hydrogen; atoms of tritium have three times the mass of ordinary hydrogen atoms.ymbol H A colorless, odorless, highly flammable gaseous element that is the lightest and most abundant element in the universe. 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).
The Kaaba is built around a sacred black stone, a meteorite that Muslims believe was placed by Abraham and Ishmael in a corner of the Kaaba, a symbol of God's covenant with Abraham and Ishmael and, by extension, with the Muslim community itself.
Alternative Titles: Kaaba, Kaba KaÊ¿bah, also spelled Kaaba, small shrine located near the centre of the Great Mosque in Mecca and considered by Muslims everywhere to be the most sacred spot on Earth. Muslims orient themselves toward this shrine during the five daily prayers, bury their dead facing its meridian, and cherish the ambition of visiting it on pilgrimage, or hajj, in accord with the command set out in the QurÊ¾Än.