Merriam-Webster Collegiate Dictionary - seam

 I. noun  Etymology: Middle English seem, from Old English seam; akin to Old English siwian to sew — more at sew  Date: before 12th century  1.  a. the joining of two pieces (as of cloth or leather) by sewing usually near the edge  b. the stitching used in such a joining  2. the space between adjacent planks or strakes of a ship  3.  a. a line, groove, or ridge formed by the abutment of edges  b. a thin layer or stratum (as of rock) between distinctive layers; also a bed of valuable mineral and especially coal irrespective of thickness  c. a line left by a cut or wound; also wrinkle  4. a weak or vulnerable area or gap found a ~ in the zone defense  • ~like adjective  II. verb  Date: 1582  transitive verb  1.  a. to join by sewing  b. to join as if by sewing (as by welding, riveting, or heat-sealing)  2. to mark with lines suggesting ~s  intransitive verb to become fissured or ridgy  • ~er noun