data

This term, meaning "facts," "information," "statistics," is really the plural of datum. In general use, however, data now appears as a singular and plural collective noun. The plural construction (These data are...) is appropriate in formal usage, although "This data is..."is more often used. The use of datum and data is not entirely comparable to that of agendum and agenda (See agendum). Agenda conveys such a strong sense of the singular that it has loosely developed its own plural, agendums. This situation does not apply to data, which has no coined plural. Those who use data as a singular obviously regard it as meaning "a body" or "a store" of information. Strictly formal writers and speakers presumably will continue to use a plural verb with data, but a majority will employ a singular or a plural verb as they choose.