ladder
noun.
steps consisting of two parallel members connected by rungs; for climbing up or down
noun.
ascending stages by which somebody or something can progress
he climbed the career ladder
noun.
a row of unravelled stitches
she got a run in her stocking
Synonym: ravel, run
verb.
come unraveled or undone as if by snagging
Her nylons were running
Synonym: run