big data is first characterized by the large size of the data, obviously the number of variable reinforces the massive aspect of the data.

Thank you Prof. Azedine for your answer, however how massive it should be? I assume it also depends on the applications subject of study.

I would say both. It is hard to say how big is big, it really depends on applications. Imaging internet data can be really massive but clinical data can be much smaller.

Thank you Dr Long for your answer.

Big data characteristics

1. Volume

2. Velocity

3. Unstructured

Data VOLUME is important, but for me the most important characteristic is their VARIETY.

https://tdwi.org/articles/2017/02/08/10-vs-of-big-data.aspx

I think i agree with Prof. Pedro. the variety of the data has great impact in saying how big a data is.