What does 'big data' mean actually?

Big data generally refers to data sets characterized by larger volume and greater variety (structured, unstructured, text and multimedia types) that are generated at a higher velocity with certain degree of veracity (e.g. quality and uncertainty) that an organization has never faced before.  Above is quoted from 1 of my articles below:

https://www.researchgate.net/publication/236863297_Using_Big_Data_Analytics_in_Information_Technology_IT_Service_Delivery

Any criteria on scale? does the definition of 'big' change with the area of research?

Think there is no fixed criteria on the scale "big" as it varies across industries as well as from time to time.  See following infographics for the 4 V of Big Data in which the quantitative metrics might be obsolete sometimes from now.

Article Using Big Data Analytics in Information Technology (IT) Serv...

Big data is a technical term referring to the humongous data availability fuelling advancement of IoT and the concomitant adoption of data analytics in virtually all domains. There are 5V's that characterise big data analytics and they are Volume(how large), velocity, veracity, variety and Value. To read more click here.

https://www.linkedin.com/pulse/20140306073407-64875646-big-data-the-5-vs-everyone-must-know

Thank you mr Han and Mr. Chinedu :) much appreciate for the quick responses.

You can refer to this paper:

https://www.researchgate.net/publication/320662254_The_role_of_open_big_data_within_the_public_sector_case_study_Jordan

Or refer to the following two presentations:

https://www.researchgate.net/publication/344548348_04_CC_BD_IoT_NidhalEl-Omari

https://www.researchgate.net/publication/344584663_Cloud_Computing_CC_Big_Data_and_Internet_of_Things_IoT

Thank you Nidhal Kamel Taha El-Omari for the resource. I have now got a better understanding of what constitutes big data.

Dear Dr. Faysal Kabir Shuvo

Big data is a collection of large datasets that requires advanced tools, techniques, and frameworks rather than traditional computing techniques.

Please look at the following examples:

• Walmart handles more than 1 million customer transactions every hour, which is imported into databases estimated to contain more than 2.5 petabytes * of data — this is the equivalent of 167 times the information contained in all the books in the USA Library of Congress.
• The amount of data produced by mankind from the beginning of time until 2003 was 5 billion gigabytes. The same amount was created in every two days in 2011, and every ten minutes in 2013. This rate is still growing enormously. (5 x 109 GB up to 2003) = (every 2 days of 2011) = (every 10 minutes of 2013)
• The Large Hadron Collider (LHC), when operational before years, generated 1GB of data per second!

Related to the aforementioned examples, big data has become a business issue or at least an issue that business people are aware of.

Big data is evolving rampantly at science symposiums, playing a most vital role across industries and business firms.

Dear Dr. Faysal Kabir Shuvo

First of all, I ask ALLAH to bless you, your family, and grant you happiness and prosperity.

related to our discussion of BIg DAta, please, do not forget that IoT is full of the following usages:

• Sensors (like microphones) which generate data based on transforming physical data (i.e. signals) to electrical data output. They are the devices that detect changes and event. change them to readable values.
• Actuators (like speakers) which are the opposite of the sensors. These devices transform electrical data to physical data.
• Transducers which transform energy from one form to another. For instance the Fuel Cell converts a Chemical Reaction to Electrical Energy.

So, “Internet-of-Things (IoT)” forms the current wave of this era of computing and it presents clearly the smart vision of this world.

It is anticipated that more than 50 billion smart things will be connected to the Internet within the next few coming years. As such, it is expected in the near future that the number of connected objects over the Internet will be more than seven times of world human population and it is anticipated to keep growing at a fast pace.

We must not forget that Internet of Things (IoT) and the Big Data (BD) are working with Cloud Computing (CC) in a complementary framework. As a result of that, “Data is the new oil of this era”.

For more information of the above discussion, please refer to my research paper "Cloud IoT as a Crucial Enabler: a Survey and Taxonomy" which can be reached by clicking at the following address:

https://www.researchgate.net/publication/334725286_Cloud_IoT_as_a_Crucial_Enabler_a_Survey_and_Taxonomy