What does frame, word, and bit mean on a FPGA
The following definitions should be applicable:


Frame - A group of words
Word - A group of bits
bit - The basic unit of any binary data - it can be either a 1 or a 0.


Typically a word would be the main unit of whatever data you are sending. For example if you are sending an RGB565 encoded image, one word would likely be a 16-bit value corresponding to a single pixel.

If sending data in chunks of multiple words, then you have a frame. In the case of images, a frame will be a single complete image. For example if you were processing a 320x240 image, 76800 pixels per frame. If each word of data was one pixel, then you would have 76800 words per frame.