soy vs soya

soy and soya both are nouns.

Word	Noun	Adjective	Verb	Adverb
soy	Yes	No	No	No
soya	Yes	No	No	No

As nouns, soy and soya are synonyms defined as:

soy and soya: the most highly proteinaceous vegetable known; the fruit of the soybean plant is used in a variety of foods and as fodder (especially as a replacement for animal protein)

Other synonyms of soy include soya bean, soybean.

As nouns, soy and soya are synonyms defined as:

soy and soya: erect bushy hairy annual herb having trifoliate leaves and purple to pink flowers; extensively cultivated for food and forage and soil improvement but especially for its nutritious oil-rich seeds; native to Asia

Other synonyms of soy include Glycine max, soja, soja bean, soya bean, soybean, soybean plant.

soy (noun)	soya (noun)
the most highly proteinaceous vegetable known; the fruit of the soybean plant is used in a variety of foods and as fodder (especially as a replacement for animal protein)	the most highly proteinaceous vegetable known; the fruit of the soybean plant is used in a variety of foods and as fodder (especially as a replacement for animal protein)
thin sauce made of fermented soy beans	erect bushy hairy annual herb having trifoliate leaves and purple to pink flowers; extensively cultivated for food and forage and soil improvement but especially for its nutritious oil-rich seeds; native to Asia
erect bushy hairy annual herb having trifoliate leaves and purple to pink flowers; extensively cultivated for food and forage and soil improvement but especially for its nutritious oil-rich seeds; native to Asia
a source of oil; used for forage and soil improvement and as food