According to the Merriam-Webster dictionary, the word research has been derived from the Middle French word 'recherche' that means 'to go about seeking' while the term 'recherche' originated from the Old French word 'recerchier': a compound word from 're- + cerchier' or 'sercher' that means 'search' in modern day English. According to the same dictionary, the earliest recorded use of the term was in 1577.

Now, if we want to understand it theoretically and in a definitive manner, research is popularly described as a 'systematic inquiry' for collecting data. These data are collected following suitable methodologies. After the data are collected, then they are analyzed and interpreted following necessary methods of data analysis. As a whole, a research analyzes and explains a phenomenon.

Research can be conducted for different purposes including:

• evaluating the validity of a hypothesis or an interpretive framework
• describing, explaining, predicting and controling an observed phenomenon
• adding new knowledge to a particular discipline
• finding solutions or ways to reach to a solution for a certain problem
• finding appropriate and feasible ways for using human knowledge to devise new applications
• supporting or refuting an existing knowledge or theory
• generating questions for further future inquiries

Now if we look closely, research necessarily involves the collection, organization, and analysis of data. Then the data are transformed into meaningful and usable information to explain a bigger phenomenon that somehow improves existing human knowledge. Often, a research project includes experts from specific professional fields and academic disciplines.

The Organisation for Economic Co-operation and Development (OECD) defines research as "Any creative systematic activity undertaken in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this knowledge to devise new applications".

John W. Creswell, an American academic and mixed methods research expert defines research as "a process of steps used to collect and analyze information to increase our understanding of a topic or issue". According to Creswell, research consists of the following three steps:

1. pose a question
2. collect data to answer the question, and
3. present an answer to the question

The Merriam-Webster Online Dictionary defines research as "studious inquiry or examination; especially : investigation or experimentation aimed at the discovery and interpretation of facts, revision of accepted theories or laws in the light of new facts, or practical application of such new or revised theories or laws."
 

References:

Merriam-Webster.com. Merriam-Webster, Inc.

OECD Glossary of Statistical Terms - Research and development UNESCO Definition. stats.oecd.org.

Creswell, J.W. (2008). Educational Research: Planning, conducting, and evaluating quantitative and qualitative research (3rd ed.). Upper Saddle River: Pearson.

CRESWELL, JOHN W (2012). EDUCATIONAL RESEARCH PLANNING, CONDUCTING AND EVALUATING QUANTITATIVE AND QUALITATIVE RESEARCH. University of Nebraska–Lincoln.