Definition of "agreement"
noun
countable and uncountable, plural agreements
(uncountable, linguistics, grammar) Rules that exist in many languages that force some parts of a sentence to be used or inflected differently depending on certain attributes of other parts.
Quotations
Having clarified what we mean by ‘Personʼ and ‘Numberʼ, we can now return to our earlier observation that a finite I is inflected not only for Tense, but also for Agreement. More particularly, I inflects for Person and Number, and must ‘agreeʼ with its Subject, in the sense that the Person/Number features of I must match those of the Subject.
1988, Andrew Radford, chapter 6, in Transformational grammar: a first course, Cambridge, UK: Cambridge University Press, page 306