What is Sanad and Matn?

In the context of Hadith transmission, the sanad refers to the chain of narration that precedes texts (matn) that attribute statements, actions, approvals or descriptions to the Prophet Muhammad, his companions or those who came after them.

For example, Imam Bukhari mentions in his book, the Sahih (Hadith 2):

Abdullah b. Yusuf told me that Malik told him that Hisham told him that Urwah told him that A’ishah told him that Al-Harith bin Hisham asked Allah’s Messenger, “O Allah’s Messenger! How is the Divine Inspiration revealed to you?” Allah’s Messenger replied, “Sometimes it is (revealed) like the ringing of a bell, this form of Inspiration is the hardest of all and then this state passes off after I have grasped what is inspired. Sometimes the Angel comes in the form of a man and talks to me and I grasp whatever he says.”

The part in bold is the sanad (chain) and the rest is the text (the matn).