EDIT Meaning
The Ogonek is a diacritical mark. »Ogonek« is polish for »little tail«.

 jsw 

EDIT Use

The Ogonek is used in the Polish and Lithuanian language, in Polish it indicates the nazalisation of a vocal. Among the Polish characters with Ogonek are »ą« and »ę«, among the lithuanian ones there are »į« and »ų«.

The Combining Ogonek is used to write characters that need an Ogonek but may not exist with an Ogonek in certain fonts.

 jsw