Lewis & Short

Ădōnĭa, ōrum, n., τὰ Ἀδώνια, the festival of Adonis. It returned annually in June, about the time of the summer solstice, and was celebrated (even in Rome; cf. Manso, Essays on Myth.) with alternate lamentations and exultations, on account of the death of Adonis, Amm. 22, 9. This festival was a symbol of the dying and reviving again of nature; cf. Hier. ad Ez. 8; Creuz. Symb. 2, 86; Böttig. Sab. 1, 261 sq.