On Thursday the House will begin a six-day period called a "district work period." Monday the Senate will begin a seven-day, "non-legislative period."

Never heard of that? Well, back in the good old days, before janitors became "maintenance engineers" and "detente" was still an acceptable word for describing the melting of the Cold War, those congressional "periods" were called "recesses."

In fact, this February period coming up used to be known affectionately as "the Lincoln-Jefferson-Jackson Day recess," when Republicans and Democrats were fond of rushing off to make long-winded speeches in honor of their party's heroes and founders.

But Congress, not unlike the victims of ethnic jokes, has become "sensitized," and because of the connotations of frivolity that "recess" implied, the word had to go.

Asked yesterday to define the difference between "recess" and "district work period," House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), explained that recess is "an ugly term the press likes to use."

O'Neill went on to add that Thursday he will in Washington and work, but Friday, Monday and Tuesday he will be holding forth in his various district offices, plumbing the feelings and needs of the folks back home.

Though the Senate discovered the "non-legislative period" euphemism a couple of years ago, the House came up with "district work period" only late last year.

The Obey commission, which was created to (among other things) rearrange the scheduling for the House, wrote in its report this rational: "It is essential that members have an opportunity to return to their districts at various intervals during the course of a session . . . To minimize interruptions in legislative work, the commission believes that traditional holidays and budget deadlines should be used as points around which to structure blocks of time for district work."

In the end, it all works out pretty much as it has in the past. In 1976, the House took 47 days of recess, plus the month of October to campaign. This year the House will take 48 days of recess, including weekend days in those periods, plus the non-election-year traditional month of August off.

Last year the Senate took 62 days, plus October. (The Senate took more time for the Democratic National Convention, perhaps because more senators hope to become presidential or vice-presidential nominees than House members do.)

This year the Senate has announced only 31 recess days, (also including weekends) but that's because Senate Majority Leader Robert C. Bryd (D-W.Va.) likes to pretend they'll adjourn by October and doesn't schedule a Columbus Day or Thanksgiving Day recess.

Actually, recesses have a more practical function of accommodating West Coast members, who complain that because of the distance they can't go home every weekend like East Coast members, whose Friday-Monday absences are responsible for Congress' "Tuesday-Thursday Club" reputation.

However, a recent poll by Louis Harris showed that 93 per cent of those citizens interviewed thought it was important for their members of Congress to get back to their district to stay in touch with their constituents.

But Harris also noted that the fact is that often more people contribute to a House member's campaign than ever see him in person.