In a pair of anomers shown as Haworth formulas, the anomer in which the hydroxy group or the alkoxy group on the anomeric carbon is pointing down is called the alpha anomer, and the one in which is pointing up is called the beta anomer.
eg. 1: anomers of D-glucopyranose
eg. 2: anomers of D-fructofuranose
eg. 3: anomers of methyl D-glucopyranoside