ladder

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. An often portable structure consisting of two long sides crossed by parallel rungs, used to climb up and down.
2. n. Something that resembles this device, especially a run in a stocking.
3. n. A means of ascent and descent: ascending the social ladder.
4. n. A series of ranked stages or levels: high on the executive ladder.
5. v. To run, as a stocking does.

Century Dictionary and Cyclopedia

1. n. A frame of wood, metal, or rope, usually portable, and consisting essentially of two side-pieces connected at suitable distances by cross-pieces, generally in the form of rounds or rungs, forming steps by which, when the frame is properly set, a person may ascend a height. A ladder differs from a stair in that it has treads, but no risers. There are many forms of ladders, adapted to different uses, as the step-ladder, standing-ladder, companion-ladder, collapsing-ladder, scaliny ladder, etc. A firemen's scaling-ladder is now used consisting of one pole only with steps on each side and a large barbed hook at the top. In use, the hook is caught in a window-sill, the fireman climbs to the window by the pole, and then raises it to the next window, and so on.
2. n. Figuratively, any means of ascending; a means of rising to eminence.
3. n. In logic, a figure illustrating the theory of the old logic concerning the relations of genera, differences, and species
4. n. Nautical See Jacob's-ladder, 1.
5. n. A series of buckets for dredging and filling which are carried up and down an incline; a bucket-conveyer.
6. n. In railroads, a track which connects by switches the ends of a series of parallel tracks and is used in sorting cars in a drill-yard. See drill-yard.

Wiktionary

1. n. A frame usually portable, of wood, metal, or rope, for ascent and descent, consisting of two side pieces to which are fastened cross strips or rounds forming steps.
2. n. That which resembles a ladder in form or use; hence, that by means of which one attains to eminence, e.g. the corporate ladder.
3. n. chiefly UK Length of unravelled fabric in a knitted garment, especially in nylon stockings.
4. n. In the game of go, a sequence of moves following a zigzag pattern and ultimately leading to the capture of the attacked stones.
5. v. firefighting To ascend a building or wall using a ladder.
6. v. of a knitted garment To develop a ladder as a result of a broken thread.

GNU Webster's 1913

1. n. A frame usually portable, of wood, metal, or rope, for ascent and descent, consisting of two side pieces to which are fastened cross strips or rounds forming steps.
2. n. That which resembles a ladder in form or use that by means of which one attains to eminence.

WordNet 3.0

1. v. come unraveled or undone as if by snagging
2. n. ascending stages by which somebody or something can progress
3. n. steps consisting of two parallel members connected by rungs; for climbing up or down
4. n. a row of unravelled stitches