(now chiefly biochemistry) Something that or someone who directs; a director or guide.
(dated, geometry) The line of motion of a describent line or surface that in so moving defines a plane or solid figure; a directrix.
adjective
That directs.
17thC, Richard Baxter, The Life of Faith, 1838, The Practical Works of Richard Baxter, Volume 3, page 690,
6. God must then be known in his three personalities; as the Father, the Word or Son, and the Spirit.
7. And these in their three causalities; efficient, dirigent, and final.
17thC, Richard Baxter, Mr. Baxter's Dying Thoughts, 1838, The Practical Works of Richard Baxter, Volume 3, page 1012,
V. I shall better know the methods and perfections of the Scripture, and all God's dirigent word and will.