ax

Definition:

An ax is tool used for cutting or chopping trees or wood.

An ax usually has a long wooden handle with a large metal blade attached to the end.
If your culture has a tool that is similar to an ax, the name of that tool could be used to translate "ax."
Other ways to translate this term could include, "tree-cutting tool" or "wooden tool with blade" or "long-handled wood-chopping tool."
In one Old Testament event, the blade of an ax falls into the river, so it is best if the tool that is described has a blade that could come loose from the wooden handle.