coke, coak

Coke or coke is an industrial product made by smelting coal--
Industrial coke is used in the manufacture of steel.
Iron and coke are used to make steel.

Coke may also be a verb ( action word ) meaning to smelt coal--
The smoke is from the furnace they use to coke coal.

Coke or coke may be a slang term for cocaine--
He was arrested for dealing coke, and he may be imprisoned or put on probation, if convicted.
He is in rehab, trying to get over his coke habit.

Coke or Coca-Cola ( always capitalized ) means the famous American soft drink, which originally contained cocaine--
"Have a Coke and a smile."
Would you like an ice-cold Coca-Cola?

Coak or coak, in carpentry, means a tenon that fits into a groove or recess, held together with dowels, or a pin or dowel holding two overlapping pieces of wood together, to keep them from sliding apart --
Cut the coak carefully, or the joint won't hold.
Use a coak here, to keep the pices together.

Now that you know that, you can say --
"He's been working hard on that coak; I bet he'd like a Coke."