I learned the terms for the interior window trim last week. The board at the bottom of the window is a stool (not a “sill” that is a exterior term) and the trim underneath that is the apron.
There are some small differences in the new window trim. The stool is less chunky and sticks out less on the sides, which is not great but fine. You can’t see it in the photo but the stool sticks out about an inch further into the room than the old trim. That is great. And the carpenter added this beautiful detail to the ends of the apron. Not easy to see, but the trim makes a right angle into the wall at the end (called a return). It’s really fine and shows off the cut in the wood.