birettaA square cap, originally with four ridges across the top, surmounted by a tuft, worn by Roman Catholic clergy (and by some in the Anglican Church). A three-sided biretta is worn by Roman Catholic clergy for liturgical celebrations.
birettinaA small skullcap worn beneath the biretta.
bireversiblereversible under the action of two linear involutions
BirganbigilA locality in the Edward River council area, southern New South Wales, Australia.
birhopaloidA type of nematocyst with two dilations on the shaft. Whatever that means. "Dilations on the shaft".
BirhorThe Birhor people are a tribal/Adivasi forest people, traditionally nomadic, living primarily in the Indian state of Jharkhand. They speak the Birhor language, which belongs to the Munda group of languages of the Austroasiatic language family.
birkarlA member of an unofficially organized group that controlled taxation and commerce in central Lappmarken in Sweden from the 13th to the 17th century.
birnessiteA soft mineral, mostly containing manganese oxides, that occurs in manganese nodules.
BirneyA design of smaller streetcar with a single four-wheel truck produced in North America between 1915 and 1930, and apparently named after Charles Birney.
birriaA Mexican dish of stewed meat (usually goat, beef or lamb; sometimes pork or chicken) and spices, typically served like a soup with (or sometimes in) tortillas.
birrieriaA restaurant (or food truck, street cart, etc) that serves birria.
BirriwaA locality in the Mid-Western council area, central New South Wales, Australia.
BirrongA suburb of Sydney in the Canterbury-Bankstown council area, New South Wales, Australia.
birthThe process of childbearing; the beginning of life; the emergence of a human baby or other viviparous animal offspring from the mother's body into the environment.
birthaversaryThe combined celebration of one's birthday and one's anniversary, especially when the two individual events are near each other in date.
birtherismA movement in the United States of America that doubts or denies that the 44th President, Barack Obama, is a natural-born U.S. citizen, thus implying that he is ineligible to be President.
birthlineA predicted line on the Hertzsprung-Russell diagram that relates the effective temperature and luminosity of pre-main-sequence stars at the start of their contraction.
birthparentA biological parent of an adopted child
birthplaceThe location where a person or an animal was born.
birthquakeAn event involving a large number of births or creations.
birthrateThe ratio of total live births to total population for a specific community or nation in a specified period; often expressed in births per thousand per year.
birthrightSomething a person is entitled to due to the circumstances of their birth, such as an inheritance or citizenship.
birthrootTrillium erectum, a perennial plant of North America with deep-red flowers.
birthsiteThe place where someone (or something) was born.