Unanimity, n.
Etymology: [L. unanimitas: cf. F. unanimité.]
The quality or state of being unanimous.
Shades of meaning
Fernald has no entry of its own for unanimity; he lists it under harmony.
Where he writes about it:
Congruity involves the element of suitableness; consistency implies the absence of conflict or contradiction in views, statements, or acts which are brought into comparison, as in the different statements of the same person or the different periods of one man's life; unanimity is the complete hearty agreement of many; consent and concurrence refer to decision or action, but consent is more passive than concurrence; one speaks by general consent when no one in the assembly cares to make formal objection; a decision of the Supreme Court depends upon the concurrence of a majority of the judges. — from harmony