My students and I often run down to the library to use the Visual Dictionary. It is a great little reference tool when you are trying to find the correct name for something. Now there is a similar reference online called, what else, the Visual Dictionary Online.
It's great for those times when a child asks you, "What's a boom on a ship?" and you've lived in a landlocked state your entire life. Or you want to sound a little more sophsticated when describing a part on a front loader by saying:
The bucket cylinder that runs the length of the arm which is connected to the boom with a hinge pin.Instead of how I normally might describe that part:
The sliding doohicky that runs the length of long thing-a-bobber which is connected to the that big doober with a hooker thing.
The online version doesn't seem quite as user friendly as the printed version. For example, I had to dig a little to find a picture of a "boom" on a sailboat. It was there but didn't come up when I searched for "boom." Still, I think it could prove a valuable resource. I've used it from home several times since discovering the site.
[Image: Screenshot from Visual Dictionary Online: http://visual.merriam-webster.com/]