Bleed- Is an extra 1/4” (1/8” on each side) added to the final size to accommodate any text or images that run over the edge, or "BLEED" off the piece. In this case (using Photoshop) set the document size to 4.5” x 5.75” at 300dpi.
Trim- Trim size is the final, cut size of the finished printed piece. In this case, 4.25” x 5.5”
Safety- Safety is at least 1/8” from the final trim size. Don’t place critical images or test beyond the safety to avoid it getting cut off when the finished pice is trimmed.