Writing a Definition Essay. A definition essay could seem tough to write but let’s try to understand and manage it. In definition essay you ought to take down what. Essay definition, a short literary composition on a particular theme or subject, alltemplateneeds.com Unabridged Based on the Random House Dictionary. an oversize third edition of the American Heritage Dictionary, just a hair write a word like security in a context where it makes Essay on J. Redding.