Etymology
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centi- 
word-forming element meaning "one hundred" or "one hundredth part," used in English from c. 1800, from the French metric system, from Latin centi-, combining form of centum "one hundred" (see hundred).
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deca- 
before a vowel, dec-, word-forming element meaning "ten," from Latinized combining form of Greek deka "ten" (from PIE root *dekm- "ten"). In the metric system, "multiplied by ten;" while deci- means "divided by ten."
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-pathy 

word-forming element meaning "feeling, suffering, emotion; disorder, disease," from Latin -pathia, from Greek -patheia "act of suffering, feeling" (from PIE root *kwent(h)- "to suffer"). Meaning "system of treatment of disease, method, cure, curative treatment" is abstracted from homeopathy (q.v.).

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neuro- 

before vowels neur-, word-forming element meaning "pertaining to a nerve or nerves or the nervous system," from Greek neura "nerve" (Galen), originally "sinew, bowstring," also neuron "sinew, string (of a bow or musical instrument); cord; penis;" in plural "strength, vigor," from PIE *(s)neuro- "tendon, sinew" (see nerve (n.)). In Greek, puppets were neurospastos, literally "drawn by strings."

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-ism 
word-forming element making nouns implying a practice, system, doctrine, etc., from French -isme or directly from Latin -isma, -ismus (source also of Italian, Spanish -ismo, Dutch, German -ismus), from Greek -ismos, noun ending signifying the practice or teaching of a thing, from the stem of verbs in -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached. For distinction of use, see -ity. The related Greek suffix -isma(t)- affects some forms.
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-ty (1)
suffix representing "ten" in cardinal numbers that are multiples of 10 (sixty, seventy, etc.), from Old English -tig, from a Germanic root (cognates: Old Saxon, Dutch -tig, Old Frisian -tich, Old Norse -tigr, Old High German -zug, German -zig) that existed as a distinct word in Gothic (tigjus) and Old Norse (tigir) meaning "tens, decades." Compare tithe (n.).

English, like many other Germanic languages, retains traces of a base-12 number system. The most obvious instance is eleven and twelve which ought to be the first two numbers of the "teens" series. Their Old English forms, enleofan and twel(eo)f(an), are more transparent: "leave one" and "leave two."

Old English also had hund endleofantig for "110" and hund twelftig for "120." One hundred was hund teantig. The -tig formation ran through 12 cycles, and could have bequeathed us numbers *eleventy ("110") and *twelfty ("120") had it endured, but already during the Anglo-Saxon period it was being obscured.

Old Norse used hundrað for "120" and þusend for "1,200." Tvauhundrað was "240" and þriuhundrað was "360." Older Germanic legal texts distinguished a "common hundred" (100) from a "great hundred" (120). This duodecimal system is "perhaps due to contact with Babylonia" [Lass, "Old English"].
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-s (1)

suffix forming almost all Modern English plural forms of nouns, gradually extended in Middle English as -es from Old English -as, the nominative plural and accusative plural ending of certain "strong" masculine nouns (such as dæg "day," nominative/accusative plural dagas "days"). The commonest Germanic declension, traceable back to the original PIE inflection system, it is also the source of the Dutch -s plurals and (by rhotacism) Scandinavian -r plurals (such as Swedish dagar).

Much more uniform today than originally; Old English also had a numerous category of "weak" nouns that formed their plurals in -an, and other strong nouns that formed plurals with -u. Quirk and Wrenn, in their Old English grammar, estimate that 45 percent of the nouns a student will encounter will be masculine, nearly four-fifths of them with genitive singular -es and nominative/accusative plural in -as. Less than half, but still the largest chunk.

The triumphs of -'s possessives and -s plurals represent common patterns in language: using only a handful of suffixes to do many jobs (such as -ing), and the most common variant squeezing out the competition. To further muddy the waters, it's been extended in slang since 1936 to singulars (such as ducks,sweets,babes) as an affectionate or diminutive suffix.

Old English single-syllable collectives (sheep, folk) as well as weights, measures, and units of time did not use -s. The use of it in these cases began in Middle English, but the older custom is preserved in many traditional dialects (ten pound of butter; more than seven year ago; etc.).

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