THESAURUS
rectilinear
arrowlike, dead straight, direct, even, flat, horizontal, in a line, level, lineal, linear, rectilineal, right, ruler-straight, smooth, straight, straight-cut, straight-front, straight-side, streamlined, true, unbending, unbent, unbowed, unbroken, uncurved, undeflected, undeviating, undistorted, uninterrupted, unswerving, unturned, upright, vertical
ROGET THESAURUS
rectilinear
Straightness
N
straightness, rectilinearity, directness, inflexibility, straight line, right line, direct line, short cut, straight,
rectilinear, rectilineal, direct, even, right, true, in a line, unbent, virgate, undeviating, unturned, undistorted, unswerving, straight as an arrow, inflexible, laser-straight, ramrod-straight.
Oscillation
N
oscillation, vibration, libration, motion of a pendulum, nutation, undulation, pulsation, pulse, alternation, coming and going, ebb and flow, flux and reflux, ups and down, fluctuation, vacillation, wave, vibratiuncle, swing, beat, shake, wag, seesaw, dance, lurch, dodge, logan, loggan, rocking-stone, vibroscope, oscillating, oscillatory, undulatory, pulsatory, libratory,
rectilinear, vibratory, vibratile, pendulous, to and fro, up and down, backwards and forwards, hither and yon, seesaw, zigzag, wibble-wabble, in and out, from side to side, like buckets in a well.