flatline

A-line, affine, airline, align, alkyne, alpine, assign, at sign, balkline, baseline, beeline, benign, bloodline, blue line, blush wine, bovine, bowline, branchline, breadline, bright-line, buntline, bustline, byline, call sign, canine, caprine, carbine, carmine, cervine, chow line, clothesline, cloud nine, coastline, combine, compline, condign, confine, consign, corvine, cosign, cutline, dateline, deadline, decline, define, design, divine, dragline, driveline, earthshine, Einstein, eiswein, end line, enshrine, entwine, equine, ethyne, fall line, fault line, feline, ferine, first-line, flight line, foul line, fräulein, frontline, front line, goal line, gold mine, grapevine, guideline, hairline, hard-line, hard pine, headline, hemline, high sign, hipline, Holbein, hotline, ice wine, incline, indign, in fine, in-line, Irvine, jawline, jug wine, landline, land mine, lang syne, lifeline, load line, longline, lupine, mainline, main line, malign, midline, moline, moonshine, neckline, off-line, old-line, online, opine, outline, outshine, ovine, Pauline, peace sign, Petrine, pipeline, piscine, pitch pine, plotline, plumb line, plus sign, pontine, porcine, potline, pound sign, propine, punch line, rapine, recline, redline, red pine, refine, reline, repine, resign, Rhine wine, ridgeline, roofline, Sabine, saline, Scotch pine, scrub pine, setline, shoreline, short line, sideline, sight line, skyline, snow line, soft-line, spring line, straight-line, strandline, straw wine, streamline, strip mine, strychnine, subline, sunshine, supine, syncline, taurine, tie-line, times sign, topline, touchline, towline, tramline, trapline, tree line, trephine, trotline, truckline, trunk line, tumpline, turbine, untwine, ursine, vespine, V sign, vulpine, waistline, white line, white pine, white wine, woodbine, yard line, zebrine, Z line