nova (n.)

"star that suddenly increases in brightness then slowly fades," 1877, from Latin nova, fem. singular adjective of novus "new" (see new), used with stella "star" (a feminine noun in Latin) to describe a new star not previously known (Tycho Brahe's published observation of the nova in Cassiopeia in 1572 was titled De nova stella). Not distinguished from supernovae until 1930s (Tycho's star was a supernova). The classical plural is novae.