The Collaborative International Dictionary of English v.0.48:

Trunkfish \Trunk"fish`\, n. (Zool.)
   Any one of several species of plectognath fishes, belonging
   to the genus Ostracion, or the family Ostraciontidae,
   having an angular body covered with a rigid integument
   consisting of bony scales. Some of the species are called
   also coffer fish, and boxfish.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Boxfish \Box"fish`\, n. (Zool.)
   The trunkfish.
   [1913 Webster]

WordNet (r) 3.0 (2006):

boxfish
    n 1: any of numerous small tropical fishes having body and head
         encased in bony plates [syn: boxfish, trunkfish]