Render has several meanings:
1. To cause a change in something. Example: Lightning struck the transformer, rendering it inoperable.
2. To create an image of something, such as by drawing. Example: Using just pencil, she made a beautiful rendering of the Notre Dame Cathedral. Or, "My computer is slow, so it will take a long time for this image to render."
3. To process animals into food and other products. Example: He got a job at the rendering plant, but the smell was so bad that he quit after just two weeks.