The Collaborative International Dictionary of English v.0.48:
Grindle \Grin"dle\, n. (Zool.) The bowfin; -- called also Johnny Grindle. [Local, U. S.] [1913 Webster]WordNet (r) 3.0 (2006):
grindle n 1: primitive long-bodied carnivorous freshwater fish with a very long dorsal fin; found in sluggish waters of North America [syn: bowfin, grindle, dogfish, Amia calva]