illustro (inl-), āvi, ātum, 1, v. a. illustris, to light up, make light, illuminate (class.; esp. freq. in the trop. signif.). Lit.: o, qua sol habitabiles Illustrat oras, maxime principum? Hor. C. 4, 14, 6: placida nocte leniter illustrante stellas, Plin. 2, 18, 16, § 80: ergastulum angustis illustratum fenestris, Col. 1, 6, 3 (but Cic. Rep. 6, 17, read lustret).

— Trop. (acc. to illustris, II. A. and B.). To make clear to the mind, to clear up, elucidate, illustrate, explain: ut ea consilia, quae clam essent inita contra salutem urbis, illustrarentur, Cic. Cat. 3, 8, 20; cf.: illustrantur, erumpunt omnia, id. ib. 1, 3, 6; id. Rep. 2, 18; Lucr. 1, 137: omnia illustrata, patefacta, comperta sunt per me, Cic. Cat. 3, 1, 3; 3, 9, 21; cf.: si modo id patefactum et illustratum est, id. Lael. 26, 97; and: jus obscurum et ignotum patefacere et illustrare, id. de Or. 1, 39, 177: philosophiam veterem Latinis litteris illustrare, id. Ac. 1, 1, 3; cf. id. Brut. 64, 228: illustrant eam (orationem) quasi stellae quaedam translata verba atque immutata, place in the right light, embellish, set off, adorn, id. Or. 27, 92; cf. id. Inv. 2, 15, 49: de illustranda oratione ut diceres, id. de Or. 3, 36, 144: orationem, Quint. 4, 3, 4; 8, 6, 14; 11, 1, 2.

— To render famous, renowned, illustrious: aliquem laudibus, Luccei. ap. Cic. Fam. 5, 14, 1: quem Brutus cognomine suo illustravit, Plin. 34, 8, 19, § 82: familiam, Suet. Galb. 3: illustrabit, mihi crede, tuam amplitudinem hominum injuria, Cic. Fam. 1, 6, 2: humilius genus illustrasse factis, Quint. 3, 7, 10: summa quibus illustratur forum ingenia, id. 10, 1, 122; cf.: Padus poenā Phaethontis illustratus, Plin. 3, 16, 20, § 117: vina maxime illustrata Messalae potu et salute, id. 14, 6, 8, § 69; Quint. 10, 1, 67; cf.: quid prius illustrem satiris Musaque pedestri? Hor. S. 2, 6, 17; Plin. 35, 10, 36, § 91.