Creating table of contents, can I read page numbers of variable definitions?

I am creating a table of contents on the first page of my documents, which needs the page number. as I edit the documents, the definitions tend to be pushed around and I have to update the page numbers, which is a pain. In Word, there is an automatic table of content generator, which can automatically update the page numbers.

Is there a way to read the page number, or find the page number of a variable so as to use this in my table of content, so it is updated automatically as I move stuff?

thanks in advance