APA Dictionary of Psychology

in a regression analysis, the weight associated with a unit change in a specific independent (predictor) variable on the dependent (outcome) variable, given the relationship of that predictor to other independent variables already in the model. This value may be standardized (see standardization) with a variance equal to 1 (in which case, it is called a beta coefficient), or it may be unstandardized and expressed in the units of the outcome variable being measured (in which case, it is called a B coefficient). Also called regression weight.