multidecade

multi- +‎ decade

multidecade (not comparable)

1. Extending over multiple decades
   • 2009, January 22, “Julia Werdigier And Nelson D. Schwartz”, in The Falling Pound Raises Fears of Nationalization‎:

     With the pound at a multidecade low and British banks requiring ever-larger injections of taxpayer cash, it is no wonder that observers have started to refer to London as “Reykjavik-on-Thames.”

• decadeslong

• multiday, multiweek, multimonth, multiyear

• decadelong, perennial, yearlong, yearslong

• demucilated