Musical America is to classical music what Rolling Stone is to rock. It’s a magazine for folks who want to read about Mahler instead of Megadeath. In business since 1898 — yes, it’s been around for three centuries — Musical America honors an artist of the year, and for 2018 that’s BSO music director Andris Nelsons. The first artist of the year was Leonard Bernstein in 1960 and since then recipients have included Yo-Yo Ma, Beverly Sills, former BSO music directors Erich Leinsdorf and Seiji Ozawa, and composers Igor Stravinsky and Benjamin Britten. Nelsons will receive the award at a ceremony at Carnegie Hall in December.