[al.ba.tross] n, pl -tross or -tross.es [prob. alter. of obs. alcatrace frigate bird, fr. Sp or Pg alcatraz pelican, fr. Ar al-ghattas, a kind of sea eagle] (1672) 1: any of a family (Diomedeidae) of large web-footed seabirds that have long slender wings, are excellent gliders, and include the largest seabirds
2. a: something that causes persistent deep concern or anxiety b: something that greatly hinders accomplishment: encumbrance