It means to work in a particular field of expertise. Like a carpenter plies his trade at woodwork or a seamstress at making clothing or a farmer at growing plants and animals.
It is Plies.
The term 'Tool of Trade' in regards to commercial vehicle insurance means the vehicle is needed to ply the trade (transportation of equipment, etc.)
Just LOOK at that hussy trying to ply her trade -on MY corner! That plywood could use another ply. I am looking to hire a ship with a captain that is unafraid to ply these waters.
Professional soldiers ply their trade. Love, hate, etc. are emotions that interfer with that trade.
San Francisco
The load range indicates the ply rating of the tire or the number of plys under the tread. A = 2 ply B = 4 ply C = 6 ply D = 8 ply E = 10 ply F = 12 ply G = 14 ply H = 16 ply J = 18 ply L = 20 ply M = 22 ply N = 24 ply This has a direct relation to the Load Index which tells you the weight the tire can carry. The more plys the more weight the tire can carry.
The suffix -lyt means decompose, split, or dissolve.
Water and Boil Proof
Successful professional soldiers control their emotions; they ply their trade, not their feelings.
A metic could ply a trade, or trade, but did not have citizenship rights, however they were required to fight in defence of Athens and had their own regiment.
Commercial ply is stronger than normal ply. Waterproofed ply is waterproofed and commercial ply is stronger but not necessarily waterproof.
Ply Board is a Board made out of Ply