Btype

Btype, usually written as B-type, is a label used in several different disciplines to categorize a subject as belonging to a broader B category. The term does not denote a single concept but rather a collection of related yet distinct meanings depending on the field.

In astronomy, B-type stars are hot, luminous blue-white stars of spectral class B. They have temperatures around 10,000 to 30,000 K and masses from about 2 to 16 solar masses. Their lifetimes are short on a cosmic timescale. Spectra show strong Balmer lines; many are main-sequence stars, while some are Be stars with emission lines and rapid rotation.

In biology and medicine, B-type refers to blood type B within the ABO system. B blood cells carry B antigens; plasma contains anti-A antibodies. Individuals with B types can receive from B or O and donate to B or AB. The Rh factor creates B+ and B− subtypes. Global prevalence ranges around 10–20%, and blood typing is essential for transfusion safety.

In psychology, Type B describes a relaxed, less competitive temperament, contrasted with Type A. The concept suggests patience and flexibility, but has been criticized for limited empirical support. It remains common as cultural shorthand rather than a precise scientific category.

Other uses include various technical labels; in practice, the exact meaning of Btype depends on the context in which it appears.