ladder
     n 1: steps consisting of two parallel members connected by rungs;
          for climbing up or down
     2: ascending stages by which somebody or something can
        progress; "he climbed the career ladder"
     3: a row of unravelled stitches; "she got a run in her
        stocking" [syn: {run}, {ravel}]
     v : come unraveled or undone as if by snagging; "Her nylons were
         running" [syn: {run}]
Source: WordNet® 2.0