Can anyone briefly explain what is Dhamma? Can anyone please explain what is Dhamma in few paragraphs if possible?

A similar question was asked by Rahula in Samyukta Nikaya but what I have is English translation of the conversation which leaves me with doubts. Also I want to establish meaning of Dhamma before asking few more questions based on it.
The term dhamma has multiple meanings in Buddhism. Dhamma is defined in the accesstoinsight.org glossary page as:


  dhamma [Skt. dharma]:(1) Event; a phenomenon in and of itself; (2)
  mental quality; (3) doctrine, teaching; (4) nibbāna. Also, principles
  of behavior that human beings ought to follow so as to fit in with the
  right natural order of things; qualities of mind they should develop
  so as to realize the inherent quality of the mind in and of itself. By
  extension, "Dhamma" (usu. capitalized) is used also to denote any
  doctrine that teaches such things. Thus the Dhamma of the Buddha
  denotes both his teachings and the direct experience of nibbāna, the
  quality at which those teachings are aimed.


If you want to know more about Dhamma, the doctrine and teachings of the Buddha, see this page.

If you want to know more about dhamma (mental quality or mental object), the fourth foundation of mindfulness, see this page, this page and the Satipatthana Sutta.