What does 'speed limit' mean?

What does 'speed limit' mean?undefined
The recommended speed for that road
The fastest speed for that road in good conditions
The minimum speed for that road in good conditions
The fastest speed except for when you are overtaking another vehicle

In New Zealand, speed limit signs are similar to those in most countries and regions around the world. The black number inside the red circle indicates the maximum speed allowed on that section of the road.