 In English, "species" behaves similarly—as a noun with identical singular and plural—while "specie" is treated as a mass noun, referring to money in the form of coins (the idea is of "[payment] in kind").Certain words which were originally plural in form have come to be used almost exclusively as singulars (usually uncountable); for example "billiards", "measles", "news", "mathematics", "physics", etc.Some of these words, such as "news", are strongly and consistently felt as singular by fluent speakers.