Continuity mistake: When Cinderella ascends the stairs with three breakfast trays, Gus is under the cup in her right hand tray. That right hand tray (with Gus) is dropped off in the first of the three rooms in order, which is Drizella's room. When screams are eventually heard and Lucifer runs to catch Gus, they come from the second (middle) door, which is Anastasia's room and it's Anastasia who had the mouse.
Continuity mistake: When the king throws his crown and breaks the window, note the lower part, a part shaped like a V is standing out. In the shot following it's now shaped like a lower case R.
Audio problem: When Lady Tremaine locks Cinderella in, she turns around in front of the mirror and says, "Oh no!" but her mouth is wide open and is not moving.
Continuity mistake: After the King tells the Duke to keep an eye on the waltz, the way the Duke holds his monocle differs between the wide angle and the POV shot.
Continuity mistake: When the stepsisters approach the prince the palace hall is suddenly empty.
Continuity mistake: In the aerial angle of the palace, when the girls are about to salute the prince, there are about a dozen girls waiting. A shot later there are twice as many.
Continuity mistake: When Cinderella arrives at the palace, in the close-up the soldiers are very close together, their shoulder pieces touching each other. In the wide angles they're a meter apart.
Continuity mistake: When the King is woken up by the Duke, the position of the red duvet keeps changing in every shot of the scene.
Continuity mistake: After Gus and Jack bring the key to Cinderella, Lucifer puts a bowl on top of the key. His paws swap from holding the upper part of the bowl to the middle part between shots.
Continuity mistake: When Jack and Gus arrive at Cinderella's room carrying the key, the key turns 180ยบ around between shots.
Continuity mistake: Right before we see Cinderella for the first time, the nest on the upper left side of her window suddenly appears between shots.
Continuity mistake: When the sisters order Cinderella to iron their dresses, the amount of stuff on the floor is not consistent with the first shots and the stuff that the sisters later throw.
Continuity mistake: When the mice open a small door and see Cinderella holding all the clothes and being scorned by the sisters, the little door keeps changing colours between shots: From solid pink to grey, to wood-grain texture.
Continuity mistake: Before the animals start to sew Cinderella's dress Jack says "Cinderella might not go to the ball", then a mouse sitting on the edge of a spool of thread with a needle showing behind her cries "What?" The shot changes and she's now sitting on the center of the spool and the needle is nowhere to be seen. This changes back and forth depending on the angle.
Continuity mistake: Cinderella places her mother's sewing book with the binding standing on the edge of the right side of the trunk. A shot later the book has moved 15 cm to the left.
Continuity mistake: When Cinderella dances with her mother's dress check the basket on the floor: the spool of thread on the floor and the scissors inside the basket suddenly appear between shots.
Continuity mistake: When Cinderella takes her dress out of the trunk the mice aren't there. A shot later they magically appear, standing on the lid.
Continuity mistake: When the birds throw the sponge into the basin, in the closeup shot the basin's edge has a simple style, as opposed to the ornamented one in the wide angles.
Continuity mistake: After the stepsisters destroy Cinderella's dress and she runs away, all the rags on the floor disappear in the aerial angle. They're not offscreen: Check the pattern of the floor and the column behind. Also, the object on the table behind her disappears too.
Deliberate mistake: The first time we see the King, the bookends and books are sketchy drawings that bear no relation to the fully detailed ones that we see afterwards.
Answer: It's a term of endearment.
Brian Katcher