spear: a long shafted weapon with a sharp metal head, carried for thrusting or throwing in battle
This is the ordinary word for a fighting spear, the long pole tipped with an iron point that a soldier held or hurled. It belongs to the world of warfare and shows up most often in the stories of Saul and David, where Saul's spear becomes almost a character of its own: he leans on it, hurls it at David, and sleeps with it stuck in the ground by his head.
The word names a real object, and the writers use it concretely. A spear can be enormous (Goliath's had a head weighing several pounds), it can be snatched as proof that an enemy was within striking distance, and it can be melted down when war finally ends and the metal is reshaped into farming tools.
Because the spear is such a vivid emblem of attack, it also turns up in poetry and prayer. When the psalmist asks God to take up spear and block the way, or pictures enemies whose teeth are spears, the weapon stands for deadly force and the threat of violence. The image works precisely because everyone knew what a spear was and did.