What do you call your child's mother-in-law or father-in-law?

I posed that question in print a few days ago, expecting little help. If a term hadn't wormed its way into the language in thousands of years, why expect one to surface in a couple of weeks?

But surprise: The answers have been as refreshing as an iced tea on a hot August day.

First, the proposals, and the clever ways that a few families handle the question:

"My husband's parents' first names are Mary and Jack," writes Nancy Austin of Arlington. "He calls them Mom and Pop, so I call them Mary-Mom and Jack-Pop." In return, Mary and Jack call Nancy their "DIL-ly," as in daughter-in-law.

Inez Matthews of Northwest writes that her daughter's mother-in-law was Portuguese. Therefore, she "always referred to me as her co-madre," Inez writes.

Maybe those Latin declensions drove you up the wall when you were in grammar school. For Persis Burns Suddeth of Bowie, however, they pointed the way to an answer. Borrowing from Latin, and from her father, Charles Burns, Persis calls her kids' in-laws "co-parenti."

"Co in-laws," suggests James G. Chandler of College Park. "Parents once removed," proposes Jean duBell of Walkersville, Md. "Friends-in-law," suggests Gloria Galyon of Silver Spring, per the suggestion of her friend Nancy Bernard.

My favorite nomination was submitted by Janice Polenzner of Arlington. She suggests "co-conspirators."

But all of this is so much useless jaw-grinding, at least in one way. There already is an "official" word for your child's in-laws--in Yiddish. Actually, there are three of them.

Phyllis Cohen of Rockville sent along the evidence: photocopies of the appropriate pages from Leo Rosten's "The Joys of Yiddish."

"Machetunim" (pronounced mokh-eh-TOON-im) means "the members of one's wife's or one's husband's extended family." That's what we in Bureaucratic Washington would call the "umbrella term." One's "machetunim" includes not only parents, but uncles named Harry, cousins named George-- everybody.

More specifically, "machetayneste" (pronounced mokh-e-TANE-es-teh) refers to the mother of your spouse. And "machuten" (pronounced muh-KHOOT-en) refers to your spouse's father.

Beside Phyllis, other correspondents pointing out the three Yiddish terms included Dorcia Begun of Silver Spring, Lillian Lukaczer of Chevy Chase, Sidney Garfinkel of Silver Spring, Isadore Grossman of Arlington, Carol Simpson of Falls Church, Patricia Denney of Greenbelt, Rose Lewis Glaser of Rockville and Anne Roberts of Kensington. Also several dozen callers. Many thanks, one and all.

Tomorrow, we untangle that other puzzler: what is the formal name for the tic-tac-toe symbol?