Wiktionary
nova remnant
n. (context star English): The debris of materials behind by the gigantic explosion of a star in a nova
Wikipedia
Nova remnant
A nova remnant is made up of the material either left behind by the gigantic explosion of a star in a nova, or from the bubbles of gas blasted away in a recurrent nova. It has an expansion velocity of around 1000 km/s, and has a lifetime of a few centuries. Considering their short lifetimes, nova remnants usually do not exist anymore by the time their light reaches us. Nova remnants are much less massive than supernova remnants or planetary nebulae.