Take the following scenario:
“For the past few weeks, I am carrying out a research on impact of environmental pollution in global warming. I planned to finish it by Feb 28th, 2008. I publish the result of my study in a local daily newspaper by March 10th, 2008.”
“So, tell me what am I executing right now?”
Your reply would be – “You are doing a research project”
“Yes, I am executing a research project.”
“Ok. you used a word ‘Project’ in earlier sentence. How can I call what I am doing right now a project?”
Definition of a Project:
A project is a temporary endeavor undertaken to create a unique product, service, or result. 
If the activity being performed has all the above characteristics then it needs to be called as a Project.
Keywords in the definition are: temporary & unique outcome.
* Temporary – It has definite beginning and end time. (10th Feb 2008 till 28th Feb 2008)
* Unique Product, Services or Results – It has results out of my research study – “A Report on Impact of Environmental Pollution in Global Warming”. And the study is unique in a manner that it conducted by considering with different organic & inorganic pollutants specific to particular area.
One other important inherent characteristic of Projects is progressive elaboration. Progressive elaboration means developing in steps, and continuing by increments.
* Progressive elaboration – The general methods explained in conducting the research was first briefed and then elaborated during the project phases with the inputs of different experts across the country.
. PMBOK® Guide – 3rd edition – Page #. 5