flat-fell seam
noun
: a strong seam with two lines of stitching showing on the right side that is produced by folding one raw edge under the other and stitching it flat or slip-stitching it on the wrong side
Word History
Etymology
obsolete English flat fell (from English flat entry 1 + obsolete English fell, noun, action of felling a seam, felled seam, from English fell entry 2) + English seam