LORELAI: Oh, oh. Well, uh . . . ugh, why don’t we move Aunt Cecile? She was always so annoying at parties. She loved the knock-knock jokes.
RORY: Mom! … You can’t just kick out Aunt Cecile.
LORELAI: Knock-knock. Who’s there? Pineapple. Pineapple who? That’s where it ended. Never fully grasped the knock-knock concept.
EMILY: She was a complete idiot. Okay, it’s decided – Cecile goes.
Aunt Cecile is one of the deceased Gilmores currently in the mausoleum, and is almost unanimously voted out to the annex as the least popular corpse, due to her habit of telling incomplete knock-knock jokes. I assume she is the sister of either Trix, or Richard’s father.
Cecile, an Anglicised French form of Cecily, was most common around the turn of the twentieth century, although it has never been very popular in the US. By the mid-twentieth century it was fairly rare.
Note that Emily is dressed in black, suitable for her role discussing death and burial.