ply

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To use diligently; wield.
• intransitive verb To engage in diligently; practice: synonym: handle.
• intransitive verb To traverse or sail over regularly.
• intransitive verb To continue offering something to (someone); ensure that (someone) is abundantly served.
• intransitive verb To ask questions or make requests of (someone) insistently.
• intransitive verb To traverse a route or course regularly.
• intransitive verb To perform or work diligently or regularly.
• intransitive verb Nautical To work against the wind by a zigzag course; tack.
• transitive verb To join together, as by molding or twisting.
• transitive verb To double over (cloth, for example).
• noun A layer, as of doubled-over cloth or of paperboard.
• noun One of the sheets of wood glued together to form plywood.
• noun A layer of rubber-coated fabric, often of nylon or polyester cords, forming the body of an automobile tire.
• noun One of the strands twisted together to make yarn, rope, or thread. Often used in combination.
• noun A bias; an inclination.

from The Century Dictionary.

• noun A fold; a thickness: often used in composition to designate the number of thicknesses or twists of which anything is made: as, three-ply thread; three-ply carpets.
• noun Bent; turn; direction; bias.
• 1 To bend; mold; shape.
• To draw: work.
• To use or employ diligently; keep on using with diligence and persistence; apply one's self steadily to; keep busy with; toil at.
• To practise or perform with diligence and persistence; pursue steadily: as, to ply one's trade.
• To attack or assail briskly, repeatedly, or persistently.
• To address with importunity or persistent solicitation; urge, or keep on urging or soliciting, as for a favor.
• To offer with persistency or frequency; press upon for acceptance; continue to present or supply: as, to ply one with drink, or with flattery.
• To apply; devote with persistency or perseverance.
• To exert; acquit.
• To bend: yield; incline.
• To keep at work or in action; busy one's self; work steadily; be employed.
• To proceed in haste; sally forth.
• To go back and forth or backward and forward over the same course; especially, to run or sail regularly along the same course, or between two fixed places or ports; make more or less regular trips: as, the boats that ply on the Hudson; the steamers that ply between New York and Fall River; the stage plied between Concord and Boston: said both of the vessels or vehicles that make the trips and of those who sail or run them.
• Nautical, to beat; tack; work to windward: as, to ply northward.
• To offer one's services for trips or jobs, as boatmen, hackmen, carriers, etc.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb obsolete To bend.
• transitive verb To lay on closely, or in folds; to work upon steadily, or with repeated acts; to press upon; to urge importunately.
• transitive verb To employ diligently; to use steadily.
• transitive verb To practice or perform with diligence; to work at.
• noun A fold; a plait; a turn or twist, as of a cord.
• noun Bent; turn; direction; bias.
• intransitive verb obsolete To bend; to yield.
• intransitive verb To act, go, or work diligently and steadily; especially, to do something by repeated actions; to go back and forth.
• intransitive verb (Naut.) To work to windward; to beat.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb transitive to bend; to fold.
• verb intransitive to flex.
• noun A layer of material. (two-ply toilet paper)
• noun A strand that, twisted together with other strands, makes up yarn or rope.
• noun colloquial Plywood.
• noun artificial intelligence, game theory In two-player sequential games, a "half-turn", or one move made by one of the players.
• noun State, condition.
• verb transitive To work at diligently.
• verb transitive To use vigorously.