oracle sql

Hello experts,
I have a table with data, from which I need to delete records keeping only the latest. here is how the table looks like

column1                               column2 (timestamp column)

abc                                         2014/11/22 08:08:38
abc                                         2015/03/06 06:10:39
abc                                         2015/03/06 08:10:39
.
.
def                                         2015/03/06 06:10:39
def                                         2015/03/06 08:10:39
def                                         2015/03/06 10:10:39

I want to keep records which have the latest time stamp like

abc                                        2015/03/06 08:10:39
def                                         2015/03/06 10:10:39

deleting the rest of the data. how can I do this in a query.