Socrates was best known for asking "why?" and "What is it?"; many times in reference to a philosphical topic like love, peace. knowledge. 

A socratic definition answers a socratic question.  If Socrates asked "what is ___?," the answer to the socratic question would be a socratic definition--not consisting of explanations, but of 'things.'  For example, Socrates would not want to know the what love is, but rather thenatureof love.  A true socratic definition is a description of the qualities or essence of the topic in question.

The definition should include:  a generality requirement (find every possible feature/example that belongs to the topic), an exclusion requirement (what does not fit with or matter to the topic) and has explanatory power (fromEuthruyphro).The definition should state the essence of the thing being defined. 

Socratic definitions must be objective, with a definite right or wrong answer.  Socrates believed that these sorts of definitions were the foundation for all learning--that nothing can be truly understoood until it is defined correctly. 

Woodruff, Paul, "Plato's Shorter Ethical Works", The Stanford Encyclopedia of Philosophy (Summer 2010 Edition), Edward N. Zalta (ed.),