Six different Hebrew words were used for knife.
Hebrew: hereb, “the waster,” a sharp instrument for circumcision (Joshua 5:2-3, literally “knives of flint;” compare Exodus 4:25); a razor (Ezek. 5:1); a graving tool (Exodus 20:25); an axe (Ezek. 26:9).
Hebrew: sakkin, a knife for any purpose, a table knife (Proverbs 23:2).
Smaller knives (Hebrew: ta'ar, Jeremiah 36:26) were used for sharpening pens.
The pruning-knives mentioned in Isaiah 18:5 (Hebrew: mizmaroth) were probably curved knives.