There are 2 main definitions of ply in English:

ply1

Syllabification: ply
Pronunciation: /plī
 
/

noun (plural plies)

1A thickness or layer of a folded or laminated material.
More example sentences
  • Gauze or gauze-like products are typically manufactured as a single piece of material folded into a several ply gauze pad.
  • The chassis was a typical composite ‘sandwich’ with inner and outer skins made up of woven laminated plies.
  • With built-up membranes, ‘thicker is better’ refers to the number of plies and not necessarily the measured thickness of the finished roof.
Synonyms
layer, thickness, strand, sheet, leaf
1.1 [usually in combination] A strand of yarn or rope: [as modifier]: four-ply yarn
More example sentences
  • A nice dense thread or 3-8 ply yarn seams to work quite nicely for a blanket stitch.
  • A rope is a ply of natural threads or synthetic fibers.
  • The ply yarns are twisted together to form cord- and the cord is the actual material used in the weaving process.
1.2The number of layers or strands of which something is made: the yarn can be any ply from two to eight
More example sentences
  • Another benefit of multiple plies is their insulating quality.
  • Even things like toilet paper came in only 1 ply or 2.
  • Mr. Johnston noted that it was apparent that the roof of the stair tower had been done after the completion of the main roof, thus resulting in some 8 plies of felt building up at the connection.
1.3 [usually in combination] A reinforcing layer of fabric in a tire: [as modifier]: a six-ply whitewall tire
2 short for plywood.
More example sentences
  • The table, as well as the maple ply and cast-steel dining chairs, are easily wiped clean after meals.
  • Although this route is more expensive than a roof coating, the single ply can be installed as a re-cover, saving the cost of tear off, if the existing roof is less than 25 percent wet.
  • Mr Constable has also designed his own home kitchen using hoop pine and maple ply.
3(In game theory) the number of levels at which branching occurs in a tree of possible outcomes, typically corresponding to the number of moves ahead (in chess strictly half-moves ahead) considered by a computer program.
More example sentences
  • This creates a ‘tree’ of analysis with moves branching at each ply.
  • This will likely include dozens of lines and several first ply candidate moves.
3.1A half-move (i.e., one player’s move) in computer chess.
More example sentences
  • For example, suppose the chances that the move at each ply of a specific line your are considering are only 40% each.
  • After a few minutes Sargon 4 was up to 7 ply and it said the best move was 19 Bd6.

Origin

late Middle English (in the sense 'fold'): from French pli 'fold', from the verb plier, from Latin plicare 'to fold'.

Definition of ply in:

There are 2 main definitions of ply in English:

ply2

Syllabification: ply
Pronunciation: /plī
 
/

verb (plies, plying, plied)

[with object]
1Work with (a tool, especially one requiring steady, rhythmic movements): a tailor delicately plying his needle
More example sentences
  • He wet his hands in a small bowl of water, and gently wiped away any dust from the stone before plying his tools to it again.
  • Penhall plies his pen widely, commenting on the dilapidated National Health Service and the nature of perception, sanity, and normalcy.
  • That's like seeing a psychiatrist plying a tendon hammer, or an orthopaedic surgeon with a pleasant bedside manner nice in a curiously old fashioned way.
Synonyms
use, wield, work, manipulate, handle, operate, utilize, employ
1.1Work steadily at (one’s business or trade); conduct: he plied a profitable export trade
More example sentences
  • According to owner Ah Hua, who has been plying a roaring trade since he opened for business 14 years ago, the non-eatery feel is what makes the place so popular.
  • Ironically Gourlay now spends much of the year plying his professional trade in Australia and is expected to base himself Down Under in the not-too-distant future.
  • The best education I got after design grad school was plying my trade within a large organization.
Synonyms
engage in, carry on, pursue, conduct, practice
archaic prosecute
2 [no object] (Of a vessel or vehicle) travel regularly over a route, typically for commercial purposes: ferries ply across a strait to the island
More example sentences
  • Strict enforcement of parking regulations is indeed a prerequisite to tide over the present crisis caused by the increasing number of motor vehicles plying through the narrow roads in the State.
  • Once the underpass is through vehicles plying on Chord Road can cross this junction without any interruption as in the case of Mekhri Circle.
  • Over 50,000 commercial vessels ply the straits each year.
Synonyms
go regularly, travel, shuttle, go back and forth
2.1 [with object] Travel over (a route) regularly for commercial purposes: the motion of the big tug as it plied the Jersey coastline
More example sentences
  • The driver refused to comply and stopped the bus in the middle of the road, before alerting his fellow drivers plying other routes.
  • All in all, Indonesia lost over half the planes plying its domestic routes.
  • For now, the airport survives as a hub for older cargo planes plying the polar route.
3 (ply someone with) Provide someone with (food or drink) in a continuous or insistent way: a flight attendant who plied them with soft drinks
More example sentences
  • They used to ply us with so much drink the night before you weren't in any shape to play.
  • We were then ushered down into a holding area where we were plied with drink and nibbles.
  • Often the hotel rooms would be double booked, so it was our job to make sure the guests came straight off the coach and into the welcome party, where they would be plied with local drink.
Synonyms
provide, supply, lavish, shower, regale
3.1Direct (numerous questions) at someone: the presiding judge plied him with a series of absurd questions
More example sentences
  • At a news conference after yesterday's meeting, which was billed to have transformation in sport as the main discussion point, journalists plied Balfour with questions about the alleged remarks.
  • With my father in the room, I'd have felt safe enough to remain but I was always sent out and therefore unable to answer the questions my older sisters plied me with.
  • And the unusually bright Lester has been plying her with all kinds of questions about death and God that she can't really answer.
Synonyms
bombard, assail, beset, pester, plague, harass, importune
informal hassle, devil

Origin

late Middle English: shortening of apply.

Definition of ply in: