torque

When I see/hear people reference torque when it pertains to nuts and bolts, what does that mean? How would I measure it without special tools? For example, I saw a clip where the mechanic says "tighten down the axle nut to the torque listed in your owner's manual..." Thanks, jF

"How much for one wrench??? I don't think I need it." So do you really need one if you want to service your own stuff? Well it's cheaper than a new sump, safer than an under or over tightened axle.