Princess Line
A top or dress with a design line that runs from the armhole to the waist/hem, or the shoulder and the waist/hem, where the bust and waist darts are incorporated into this seam.
Examples
Image 1: This fashion flat shows a dress which has a princess line from the armhole to the hem; the princess line is highlighted in pink. This is my Lina dress pattern.
Image 2: Front and back view of my Lina Dress. The princess line is not obvious on the garment itself although it can be used to effect with striped fabric.
Image 3: This fashion flat shows a dress which has a princess line from the shoulder to the waist; the princess line is highlighted in pink. This is my Jasnah dress pattern.
Image 4: Front and back view of my Lina Dress. Again the princess line is not obvious on the garment.