etymology. Etymology is the study of the roots or words. You can sometimes define a word by giving its root meaning and thus showing where it came from:
 
Intuitioncomes from the Latin word in (meaning “in” or “into”) and tueri (meaning “.look” or “gaze”). Literally, therefore, it means a "looking inward."
 
7.      Defining by constituents. You can define a word by presenting the constituents it consists of.
 
What is the difference between the British Isles, Britain, the United Kingdom and England? These terms are so often confused that we had better start by distinguishing them.
The British Isles consists of two large islands; one is called Ireland and the other Britain.
Britain, or Great Britain, is the larger of these two islands, and it is divided into three parts: Scotland, Wales and England.
The United Kingdom is that part of the British Isles ruled over by the Queen. It consists of Scotland, Wales and England (i.e. the whole of Britain), and also about one-sixth of Ireland, the Northern part. The rest of Ireland is self-governing, and it is called the Republic of Ireland. The full title of the United Kingdom is therefore ‘The United Kingdom of Great Britain and Northern Ireland’.
—  The United Kingdom of Great Britain and Northern Ireland
 
A definition may use more than one of these methods, especially if it runs to a paragraph or longer. Here, for instance, from an article on cancer research, is a definition of interferon:
 

Defining bycomparison
Defining bynaming the class
       Interferonis a large hormone-like protein produced by the cells of all
Presenting thebackground
 
 
 
 
 
 
 
Defining by giving the distinct features
 
 
Defining by etymology
 
vertebrate animals. It was discovered in 1957 in Britain by virologists Alick Isaac and Jean Lindenmann during their investigation of a curious phenomenon: people are almost never infected by more than one virus at a time. Seeking an explanation, researchers infected cells from chick embryos with influenza virus. What they found was a substance that protected the chick cells from both the flu and other virus. Because it interfered with the infection process, it was dubbed interferon.

 
This definition combines analysis with comparison and with etymology of a sort — a little digging into the origin of the word. Interferon is a protein; that is its class. It is compared to hormones — described as hormone-like — and its name is said to have come from the word interfere.
The method of definition is quite useful for clarifying abstract terms that may be interpreted differently by different people. Unlike concrete terms, which refer to objects that can be touched or measured, abstract terms represent qualities or emotions apart from any particular objects. The following paragraph defines the abstract word Patriotism.
 

Defining byanalysis:
    class & features
 
 
 
 
Defining byconstituents
 
 
 
 
 
Patriotism means the love of one’s country.It makes one ready to sacrifice his life for his country, and to do many other deeds which can bring benefits to his people. The effect is very great when it is exercised by all the people of a country. It makes a country strong, and its history glorious. It also improves a man’s character and secures for him a widespread fame. To us, ordinary Chinese people, to love our country, to support her government, to observe her laws, to pay fair taxes into her treasury, to work hard, to do our best so as to make contributions to her and even to sacrifice our life for her when necessary constitute our great patriotism.

 
Indicators of definition:
 
       this word means/signifies                       that is
       the meaning of this word is                   namely
       is to be/must be distinguished from              by…I mean 
       not to confused with                              by…is meant
       … constitute…                                      … consist of…
 

Comparison and contrast

 
Paragraphs may be developed by