square one(n = noun.state) - the situation in which you begin an endeavor and to which you return if your efforts fail; "the police are now back at square one after having arrested and released 27 men"; "she has tried to diet but always ends up back at square one"
is a kind of situation, state of affairs

as one, at one, at one time, beneath one, bevel square, beyond one, carpenter's square, characteristic root of a square matrix, eigenvalue of a square matrix, fair and square, fast one, for each one, for one, for one thing, from each one, go one better, hundred and one, in one case, in one ear, knight of the square flag, latin square, loved one, magic square, market square, naked as the day one was born, number one, number one wood, on one hand, on the one hand, one, one after another, one and all, one and only, one at a time, one by one, one c, one dollar bill, one horse, one hundred, one hundred eighty, one hundred fifteen, one hundred fifty, one hundred fifty-five, one hundred five, one hundred forty, one hundred forty-five, one hundred ninety, one hundred one, one hundred seventy, one hundred seventy-five, one hundred sixty, one hundred sixty-five, one hundred ten, one hundred thirty, one hundred thirty-five, one hundred twenty, one hundred twenty-five, one iron, one million million, one million million million, one of the boys, one of these days, one one's coattails, one percent, one piece, one shot, one sided, one thousand, one thousand million, one thousand thousand, one time, one upmanship, pounds per square inch, public square, pull a fast one, pull a fast one on, put one across, put one over, rolled into one, set square, six of one and half a dozen of, square, square and rabbet, square away, square block, square bracket, square dance, square dancer, square dancing, square deal, square dealing, square foot, square inch, square knot, square matrix, square meal, square measure, square meter, square metre, square mile, square nut, square off, square root, square sail, square shooter, square toes, square up, square yard, squareflipper square flipper, t square, thousand and one nights, times square, to each one, to one ear, trafalgar square, try square, word square, young one