Moderate, v. t. [imp. & p. p. Moderated; p. pr. & vb. n. Moderating.]
1. To restrain from excess of any kind; to reduce from a state of violence, intensity, or excess; to keep within bounds; to make temperate; to lessen; to allay; to repress; to temper; to qualify; as, to moderate rage, action, desires, etc.; to moderate heat or wind. By its astringent quality, it moderates the relaxing quality of warm water. Arbuthnot. To moderate stiff minds disposed to strive. Spenser.
2. To preside over, direct, or regulate, as a public meeting; as, to moderate a synod.
3 other Webster entries under this spelling
Moderate, a.
Kept within due bounds; observing reasonable limits; not excessive, extreme, violent, or rigorous; limited; restrained; as: (a) Limited in quantity; sparing; temperate; frugal; as, moderate in eating or drinking; a moderate table. (b) Limited in degree of activity, energy, or excitement; reasonable; calm; slow; as, moderate language; moderate endeavors. (c) Not extreme in opinion, in partisanship, and the like; as, a moderate Calvinist. A number of moderate members managed ... to obtain a majority in a thin house. Swift.
(d) Not violent or rigorous; temperate; mild; gentle; as, a moderate winter. "Moderate showers." Walter. (e) Limited as to degree of progress; as, to travel at moderate speed. (f) Limited as to the degree in which a quality, principle, or faculty appears; as, an infusion of moderate strength; a man of moderate abilities. (g) Limited in scope or effects; as, a reformation of a moderate kind. Hooker.
Moderate, n. (Eccl. Hist.)
One of a party in the Church of Scotland in the 18th century, and part of the 19th, professing moderation in matters of church government, in discipline, and in doctrine.
Moderate, v. i.
1. To become less violent, severe, rigorous, or intense; as, the wind has moderated.
2. To preside as a moderator. Dr. Barlow [was] engaged ... to moderate for him in the divinity disputation. Bp. Barlow's Remains (1693).
Shades of meaning
Fernald has no entry of its own for moderate; he lists it under abate, alleviate, slow.
Where he writes about it:
Assuage is, by derivation, to sweeten; mitigate, to make mild; moderate, to bring within measure; abate, to beat down, and so make less. — from alleviate
We abate a fever; lessen anxiety; moderate passions or desires; lighten burdens; mitigate or alleviate pain; reduce inflammation; soften, assuage, or moderate grief; we lighten or mitigate punishments; we relieve any suffering of body or mind that admits of help, comfort, or remedy. — from alleviate