i Register
In some senses, fay is marked as obsolete, slang, US. Watch for register when choosing this word.
verb
To fit, to add.
To join (pieces of timber) tightly. The long edges of the staves of a barrel have to be fayed so that when it is assembled it will not leak.
I have a strip cutter and I can cut the exact widths I need to fit, they are easy to fay together and attach very firmly to the bulkheads.
Of pieces of timber: to lie close together.
To fadge.
adj
Fitted closely together.
Under the four outer corners of the horizontal frame platform 22 are four tubular leg sleeves 23 that are fay together one at each outer corner.
noun
A fairy.
that mighty Princesse did complaine / Of grieuous mischiefes, which a wicked Fay / Had wrought [...].