Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

proptĕrĕā, adv. [propter-is], therefore, for that cause, on that account (syn.: ideo, idcirco, inde; class.): quia mihi natalis est dies, propterea te vocari ad cenam volo, Plaut. Capt. 1, 2, 71: proptereaquia, Cic. Div 1, 14, 25; 2, 22, 49; id. Lael. 2, 6: haec propterea de me dixi, ut, etc., id. Lig. 3, 8: propterea quoniam, Gell. 3, 6: propterea, quod, because that, Cic. Rep. 1, 6, 11; id. Fam. 9, 18, 1.
Esp. with reference to something just said: scio, Et pol propterea magis nunc ignosco tibi, Ter. Eun. 5, 2, 40; id. And. 4, 2, 10: id propterea nunc hunc venientem sequor, with that in view, therefore, id. ib. 2, 5, 3: ergo proptereane, etc., id. Hec. 1, 1, 6.