Type of knife or something?

This is probably trash but quite curious what this would've been? I found it broken and couldn't find the rest. This piece is about 5" long and has a wavy toothed edge. I was thinking an iron knife of some sort (?). If it helps, I dug this at a park that was once a civil war training ground (doubtful its from that era).

Any info, generic or specific, is appreciated. Thanks!