Sometimes the best way to describe the meaning of a word is to show a picture of what it represents. But sometimes you need to go the other way: you have a picture of something in your mind and you need to find the word for it.
For example, what do you call the thing in a multi-speed bicycle that moves the chain from one set of gears to another?
In OmegaWiki we have a new set of pages of pictures with labels. When you hover with your mouse over one of the labeled parts of the picture, the word for it appears. If you click on the labeled part, you are taken to the Defined Meaning page of the word, where you can see its definitions, synonyms and translations in other languages. The labels are in your default language, but you can switch to another version of the picture using the language links in the left column.
You can access an index of the Visual Dictionary here. Our first pictures are of a human skull, a flower, a bicycle, a tugboat, and a family tree.
A family tree is a good way to visualize the meaning of kinship terms. Did you know that Turkish has many specific kinship terms such as "dünür", which means "parent-in-law of a person's child"? You can see them all in the Visual Dictionary in this diagram.
Commons has many language-neutral, labeled diagrams at  that can be readily used in the OmegaWiki Visual Dictionary. If you are familiar with the terminology of one of those pictures, feel free to import it into OmegaWiki. You may want to look at our help page on how to create such labeled diagrams.