declension = the variation of the form of a noun, pronoun, or adjective, by which its grammatical case, number, and gender are identified.

Etymonline for `declension {noun}' rechannels to decline (v.):

1. ... from Latin declinare "to lower, avoid, deviate, to bend from, inflect," from de- "from" (see de-) + clinare "to bend," from PIE * klei-n-, suffixed form of * klei- "to lean" (see lean (v.)). Sense has been altered since c. 1400 by interpretation of de- as "downward. ...

inflection = inflexion = {Grammar} A change in the form of a word (typically the ending) to express a grammatical function or attribute such as tense, mood, person, number, case, and gender:

2. Etymonline for `inflection {noun}' rechannels to inflect (v.):

... from in- "in" (see in- (1)) + flectere "to bend" (see flexible). Grammatical sense is attested 1660s; pronunciation sense (in inflection) is c. 1600. ...

3. About the grammatical meaning of decline, does the prefix de- mean from or downward?
In other words, which sense applied to decline: that before c. 1400, or after?

4. What does the directionality of these nouns mean? In other words, how does declension entail bending DOWNWARD or FROM, whereas an inflection entails bending INWARDS?

Please help me dig deeper than the definitions, which I already understand and so ask NOT about. I heed the Etymological Fallacy. But what are some right ways of interpreting these connotations of definition, to make the etymology feel reasonable and intuitive?

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    Very simply, a declension is a list of the variations of a form in a paradigm. Each of the forms in a paradigm varies from ('bends from', de-clinare, inflectere) some "root" word, thus capio, capis, capit; capimus, capitis, capiunt are the six forms of the present tense for capere 'grab, take' (the Latin verb cognate with English have -- Latin C tends to correspond to an H in English, like 'cardio' and 'heart' or 'canine' and 'hound', by Grimm's Law. The metaphor of a root with various stems and forms is very ancient in grammatical discourse. – jlawler Apr 26 '15 at 22:36

Declinatio is a technical term in Latin grammar, which has been adopted into English. Its technical use is described as follows in Lewis and Short:

“Of gramm. lang.: variation, inflection.

(α). In the older grammarians, every change of form which a word undergoes; as declension, strictly so called, conjugation, comparison, derivation, etc., Varr. L. L. 8, § 2 sq.; 10, § 11 sq.; Cic. de Or. 3, 54; cf. “also of declension in its stricter sense,” Quint. 1, 4, 29; 1, 5, 63; “of conjugation,” id. 1, 4, 13; “of derivation,” id. 8, 3, 32; 2, 15, 4.—

(β). Among the later grammarians, of declension, properly so called, as distinguished from conjugatio, comparatio, derivatio, etc. So, Donatus: in declinatione compositivorum nominum, p. 174 P. (p. 13 Lind.).”


The idea of “bending down” is connected with the concept of “case”, for Latin casus, translating Greek ptosis “falling”. If you write the different forms of a noun in a list you will “fall” down the list when you move from one form to another.

  • 1
    SOURCE: 'The comments found in various scholia on the Τέχνη suggest that case markings represent the notion of “falling” in the sense that the[y] have “fallen” away from abstract lexical entities into more fully grammaticalized forms.' I seem to remember that in Latin pedagogy the nominative was often referred to as the 'upright' (rectus) case. – StoneyB on hiatus Apr 25 '15 at 18:04
  • @StoneyB Thanks. Sorry if I missed this, but did you explain the significance of in + to bend for inflection? How does inflection BEND + IN (whatever it ought to)? – NNOX Apps May 5 '15 at 1:39
  • @LawArea51Proposal-Commit Think 'bend' in the sense 'bow', so you have the same sense of deviating from an 'upright' position. I'm not gonna even try to sort out what any particular language might 'mean' by any particular preposition in any particular context; your study of English should by now have taught you what a futile effort that is. – StoneyB on hiatus May 5 '15 at 12:54

Inflection goes inward, because the parts of a clause most central to the meaning are the most likely to be marked on the verb, those most peripheral, least likely. Declension goes downward in the grammatical structure of a sentence, because at the top of the structure we find the least oblique forms, at the bottom, the most oblique.

Law Area asks further (in a comment):

What do you mean by marked on the verb?

Marked on the verb by the addition of an inflection suffix agreeing with the subject, perhaps also the object, and perhaps other sentence arguments.

What is meant by the top of the structure? Which structure?

The top of an inverted tree of the usual sort giving a diagram of the structure of a sentence.

And oblique?

Oblique is a term from traditional grammar referring to grammatical cases most different from the nominative and, in a declension, ordinarily given toward the bottom.

A suitable dictionary of linguistic terms would do a better job than I at defining these things.

  • I would call this a wild guess. The historical origin of these terms is explained in my answer. – fdb Apr 25 '15 at 9:47
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    I wasn't intending to give the historical origin. I was making up a story to help the questioner make sense of the ideas. I think that is what was asked for. – Greg Lee Apr 25 '15 at 14:16
  • Thanks. Yes; I was. Would you please reify your stories, though? What do you mean by marked on the verb? What is meant by the top of the structure? Which structure? And oblique? – NNOX Apps May 5 '15 at 1:42
  • Will you please to respond in your answer, which is easier to read than comments? – NNOX Apps May 5 '15 at 1:42
  • @LawArea51Proposal-Commit If you have trouble reading comments, try zooming in. – snailplane May 5 '15 at 5:31

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