I heard that many disciplines whose names end with the letter “s” as if they were plural actually came from Greek/Latin words of plural form (e.g. mathematics from mathematika). It seems like, however, some disciplines like astronomy or philosophy also had Greek origins and their original words also ended with the letter “a”.

I have no knowledge of Greek or Latin; does it just mean that those Greek words are not plural? Or are there some reasons why such disciplines get to obtain English names with no “s” at the end?

  • To add to your confusion, consider that English has both economy and economics.
    – Sven Yargs
    Commented Dec 14, 2017 at 8:15
  • The Greeks had many philosophies (Stoicism, Epicurianism, etc), which might explain the plural form. Now, we lump them all together as one subject.
    – Mick
    Commented Dec 14, 2017 at 8:21
  • I am not going to comment about Greek, but, in Latin, masculine and feminine nouns in the first declension ended in "a" when singular whereas neuter nouns in the second declension ended in "a" when plural. Rules of inflection in Latin are orders of magnitude more complex than in English. There are five declensions of nouns in Latin, each declension having its own rules, and each declension having five cases in singular and plural. Commented Dec 14, 2017 at 9:03
  • How many universes are there?
    – Hot Licks
    Commented Dec 14, 2017 at 18:51

2 Answers 2


This is from etymonline :

in the names of sciences or disciplines (acoustics, aerobics, economics, etc.), a 16c. revival of the classical custom of using the neuter plural of adjectives with Greek -ikos "pertaining to" (see -ic) to mean "matters relevant to" and also as the titles of treatises about them.

Subject matters that acquired their English names before c. 1500, however, tend to be singular in form (arithmetic, logic, magic, music, rhetoric). The grammatical number of words in -ics (mathematics is/mathematics are) is a confused question.

Greek words give rise to the '-ology' endings from λογος, logos - 'word'; to the '-nomy' endings from νομια, nomia - 'rule' or 'law'; and to the '-ics' endings from ικος, ikos - 'pertaining to'.


It is from the Latin and Greek suffix -ia which in English has become -y, probably for assonance with the original French astronimie:

Astro -nomy

a combining form of Greek origin meaning “distribution,” “arrangement,” “management,”:

  • astronomy; economy; taxonomy.

From Greek -nomia law. nomo-, -y

(Random House Dictionary)


c. 1200, "astronomy, astrology, scientific or occult study of heavenly bodies," from Old French astrenomie "astronomy, astrology," from Latin astronomia, from Greek astronomia.


suffix indicating state, condition, or quality; also activity or the result of it (as in victory, history, etc.), via Anglo-French and Old French é, from Latin -ia, Greek -ia, from PIE *-a-, suffix forming abstract or collective nouns. It is etymologically identical with -ia and the second element in -cy, -ery, -logy, etc.


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