Weighted average number of ordinary shares outstanding during the period is the number of ordinary shares outstanding at the begining of the period adjusted by the number of ordinary shares bought back or issued during the period multiplied by a time weighting factor.
Weighted average number of ordinary shares outstanding during the period is specifically discussed in IAS 33 Earnings per Share.
Source: Glossary of Term of IFRSs issued as at 31 December 2008.
