I asked the same thing earlier and this is what patrick mcfadin replied: "It's not worded well. Essentially it's saying there is a 2B limit on a row. It should be worded a 'CQL row'"

I hope helps. 

Cheers,
Hannu

On 6.9.2013, at 8.20, J Ramesh Kumar <rameshj1977@gmail.com> wrote:

Hi,

http://wiki.apache.org/cassandra/CassandraLimitations

In the above link, I found the below limitation,

"The maximum number of cells (rows x columns) in a single partition is 2 billion.".

Here what does "partition" mean ? Is it node (or) column family (or) anything else ?

Thanks,
Ramesh