Part 390

1. To throw rays of light upon; to illuminate; to brighten; to adorn with luster.

Thy smile irradiates yon blue fields.

Sir W. Jones.

2. To enlighten intellectually; to illuminate; as, to irradiate the mind. Bp. Bull.

3. To animate by heat or light. Sir M. Hale.

4. To radiate, shed, or diffuse.

A splendid façade, . . . irradiating hospitality.

H. James.

Ir*ra"di*ate, v. i. To emit rays; to shine.

Ir*ra"di*ate (?), a. [L. irradiatus, p. p.] Illuminated; irradiated. Mason.

Ir*ra`di*a"tion (?), n. [Cf. F. irradiation.]

1. Act of irradiating, or state of being irradiated.

2. Illumination; irradiance; brilliancy. Sir W. Scott.

3. Fig.: Mental light or illumination. Sir M. Hale.

4. (Opt.) The apparent enlargement of a bright object seen upon a dark ground, due to the fact that the portions of the retina around the image are stimulated by the intense light; as when a dark spot on a white ground appears smaller, or a white spot on a dark ground larger, than it really is, esp. when a little out of focus.

Ir*rad"i*cate (?), v. t. To root deeply. [R.]

Ir*ra"tion*al (?), a. [L. irrationalis: cf. F. irrationnel. See In- not, and Rational.]

1. Not rational; void of reason or understanding; as, brutes are irrational animals.

2. Not according to reason; absurd; foolish.

It seemed utterly irrational any longer to maintain it.

I. Taylor.

3. (Math.) Not capable of being exactly expressed by an integral number, or by a vulgar fraction; surd; -- said especially of roots. See Surd.

Syn. -- Absurd; foolish; preposterous; unreasonable; senseless. See Absurd.

Ir*ra`tion*al"i*ty (?), n. The quality or state of being irrational. "Brutish irrationaliity." South.

Ir*ra"tion*al*ly (?), adv. In an irrational manner. Boyle.

Ir*ra"tion*al*ness, n. Irrationality.

Ir`re*but"ta*ble (?), a. Incapable of being rebutted. Coleridge.

Ir`re*cep"tive (?), a. Not receiving; incapable of receiving.