As a Noun:
1. Facts, details and ideas which say why something happened or is the way it is. English = explanation.
2. An account of what a person, thing or event is like, especially what it looks like. English = description.
3. A statement giving the meaning of a word or a sign, especially in a dictionary. English = definition
As a Verb or Adjective:
1. To communicate facts, details and ideas about something to say why it happened or is the way that it is. English = explain.
2. To say what a person, thing, or event is like, especially what it looks like. English = describe.
3. To say exactly what something is or to say exactly what a word or a sign means. English = define