Bubby

Bubby (many alternate spellings) is the fun and energetic maternal grandmother of Francine and Catherine, and the mother of Laverne, and also the mother-in-law of Oliver.

'Bubbie' is a Yiddish term of endearment which is interchangeable with 'grandmother', the original Yiddish being bubeleh. Bubbie's last name is unknown because she is on Laverne's side of the family. She practices the Jewish religion, like Francine's family. She went to Francine's family's apartment to celebrate Yom Kippur in "Is That Kosher?".

She first appeared in Arthur's Perfect Christmas, but became recognized as an official character in Is That Kosher?. In "The Great MacGrady," it was revealed that her husband died of cancer. She is one of two guest stars that have returned with speaking roles, with Lance Armstrong being the only other guest star.

She possibly has Obsessive Compulsive Disorder, because in "Grandpa Dave's Memory Album" she thoroughly cleans Francine's apartment, and she even cleans Arthur's dishes after she eats over at his house with Francine.

Laverne Frensky
Laverne and Bubby have a good relationship, as they are mother and daughter. Bubby at times picks on her daughter (along with her son-in-law), saying that she hardly feeds Francine and Katherine, as well as when she says that their apartment is not clean.

Francine Frensky
Francine and Bubby get along well too, and Francine seems to be the person with the most interaction with Bubby. The two do many things together.

Oliver Frensky
Not much interaction is seen between Oliver and Bubby, but it can be (deeply) assumed that she loves him a lot.

Catherine Frensky
When Bubby arrived for Yom Kippur, she energetically embraced both Francine and Catherine and called then her "favorite grandchildren". She then told Catherine that, although she was turning into "such a beauty" that, "...blue really isn't your color, darling..."

Arthur

 * 702a Francine's Split Decision
 * 1108a Francine's Pilfered Paper
 * 1201a Is That Kosher?
 * 1506a Grandpa Dave's Memory Album

Specials

 * Arthur's Perfect Christmas

Name
Her name has multiple official spellings:
 * Bubby
 * Bubbe
 * Bubba