When you're hanging around websites and groups online, it can get rather confusing when people use different terms for the same thing, or use the same word in different ways. So here's a few definitions.
The thing you use with the brush tool (or the pencil tool). You can select different brush shapes, these are defined by special brush files in the brushes directory.
However, this can be commonly misused to describe a simple resource image, especially if it is 100x100 to be used for making LiveJournal icons.
The thing you use with the gradient tool, graduating from one colour to another. They can be defined and edited separately and saved in special gradient files in the gradients directory.
However, this is also misleadingly used to apply to a resource image (or even brush) which was created with the gradient tool, and thus has an example of a gradient in it.
The thing you use with the "bucket fill" tool when you select the "fill with pattern" option. These are defined by special pattern files in the patterns directory.
- resource image:
An image used as a resource, generally cut-and-pasted into a layer in the image that you're working on.
Usually used to describe a pattern or a brush or a resource-image which has an interesting texture.