pons asinorum



New Latin pons asinorum, from Latin pōns (bridge) + genitive plural of asinus (ass).


pons asinorum (uncountable)

  1. (logic) A method for finding the middle term of a syllogism in Aristotlean analytics. [from 17th c.]
  2. An obstacle which will defeat a beginner or foolish person. [from 17th c.]
  3. (geometry) A proposition in Euclid stating that the angles at the base of an isoceles triangle are equal. [from 18th c.]
    • 1751, Tobias Smollett, The Adventures of Peregrine Pickle, I.18:
      [H]e had scarce advanced beyond the Pons Asinorum, when his ardour abated, the test of truth by demonstration did not elevate him to those transports of joy with which his preceptor had regaled his expectation; and before he arrived at the fortieth and seventh proposition, he began to yawn drearily [] .


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pōns asinōrum m (genitive pontis asinōrum); third declension

  1. literally, "the Bridge of Asses": the geometric theorem (Euclid's fifth) that the two angles opposite the equal sides of an isosceles triangle are also equal
  2. a difficult early test that must be passed if further progress is to be made


Third-declension noun (i-stem) with an indeclinable portion.

Case Singular Plural
Nominative pōns asinōrum pontēs asinōrum
Genitive pontis asinōrum pontium asinōrum
Dative pontī asinōrum pontibus asinōrum
Accusative pontem asinōrum pontēs asinōrum
pontīs asinōrum
Ablative ponte asinōrum pontibus asinōrum
Vocative pōns asinōrum pontēs asinōrum


  • Dutch: ezelsbrug (calque), ezelsbruggetje
  • German: Eselsbrücke (calque)