PHENOMENA

noun (plural -nas) Date: 1576 phenomenon , Usage: Phenomena has been in occasional use as a singular for more than 400 years and its plural ~s for more than 350. Our evidence shows that it is primarily a speech form used by poets, critics, and professors, among others, but one that sometimes turns up in edited prose . It is etymologically no more irregular than stamina, agenda, and candelabra, but it has nowhere near the frequency of use that they have, and while they are standard, ~ is still rather borderline.