Consistence, Consistency, n.
Etymology: [Cf. F. consistance.]
1. The condition of standing or adhering together, or being fixed in union, as the parts of a body; existence; firmness; coherence; solidity. Water, being divided, maketh many circles, till it restore itself to the natural consistence. Bacon. We are as water, weak, and of no consistence. Jer. Taylor. The same form, substance, and consistency. T. Burned.
2. A degree of firmness, density, or spissitude. Let the expressed juices be boiled into the consistence of a sirup. Arbuthnot.
3. That which stands together as a united whole; a combination. The church of God, as meaning whole consistence of orders and members. Milton.
4. Firmness of constitution or character; substantiality; durability; persistency. His friendship is of a noble make and a lasting consistency. South.
1 more senses
5. Agreement or harmony of all parts of a complex thing among themselves, or of the same thing with itself at different times; the harmony of conduct with profession; congruity; correspondence; as, the consistency of laws, regulations, or judicial decisions; consistency of opinions; consistency of conduct or of character. That consistency of behavior whereby he inflexibly pursues those measures which appear the most just. Addison. Consistency, thou art a jewel. Popular Saying.
Shades of meaning
Fernald has no entry of its own for consistency; 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