mōnstrō

Ostendere means to show, as far as one makes something observable, lets it be seen, and does not keep it secret, like φῆναι, ἐμφανίσαι; monstrare (intensive from μανθάνειν) means to show, as far as one imparts information thereby; lastly, declarare, to make evident, as far as one makes a thing clear, and dispels doubt, like δηλῶσαι.

Auguria and auspicia are appearances in the ordinary course of nature, which for the most part possess a meaning for those only who are skilful in the interpretation of signs; auguria (from augur, αὐγάζειν) for the members of the college of augurs, who are skilled in such things; auspicia, for the magistrates, who have the right to take auspices: whereas prodigia, ostenta, portenta, monstra, are appearances out of the ordinary course of nature, which strike the common people, and only receive a more exact interpretation from the soothsayer: lastly, omina (ὄθματα, ὄσσαι) are signs which any person, to whom they occur, can interpret for himself, without assistance. The primary notion in prodigium is, that the appearance is replete with meaning, and pregnant with consequences; in ostentum, that it excites wonder, and is great in its nature: in portentum, that it excites terror, and threatens danger; in monstrum, that it is unnatural and ugly. (v. 178.)