One meaning of Sunnat is: a way, pattern, a road leading to a watering place. The other meaning, which I am referring to, is in a Fiqhi (Jurisprudential) sense (like 'Fardh' 'Waajib', etc.) A Mujtahid like Imaam Abu Hanifa (A.R) informs us whether something is Fardh, Waajib, Sunnat, Nafl, etc.