• Webster's Revised Unabridged Dictionary
    • Protasis A proposition; a maxim.
    • Protasis The first part of a drama, of a poem, or the like; the introduction; opposed to epitasis.
    • Protasis (Gram) The introductory or subordinate member of a sentence, generally of a conditional sentence; -- opposed to apodosis. See Apodosis.
    • ***
Century Dictionary and Cyclopedia
  • Interesting fact: The "if" and "then" parts of conditional ("if P then Q") statement are called the protasis (P) and apodosis (Q).
    • n protasis A proposition; a maxim.
    • n protasis In grammar and rhetoric, the first clause of a conditional sentence, being the condition on which the main term (apodosis) depends, or notwithstanding which it takes place: as, if we run (protasis), we shall be in time (apodosis); although he was incompetent (protasis), he was elected (apodosis). see apodosis.
    • n protasis In the ancient drama, the first part of a play, in which the several persons are shown, their characters intimated, and the subject proposed and entered on: opposed to epitasis.
    • n protasis In ancient prosody, the first colon of a dicolic verse or period.
    • ***
Chambers's Twentieth Century Dictionary
    • n Protasis prot′a-sis (rhet.) the first part of a conditional sentence—opp. to Apodosis: the first part of a dramatic composition
    • ***


Webster's Revised Unabridged Dictionary
L., fr. Gr. pro`tasis, fr. protei`nein to stretch before, forward; pro` before + tei`nein to stretch
Chambers's Twentieth Century Dictionary
Gr.,—pro, before, tasis, a stretching, teinein, to stretch.


In literature:

It doubles itself in the middle of his life, reflects itself in another, repeats itself, protasis, epitasis, catastasis, catastrophe.
"Ulysses" by James Joyce
Respecting the imperfect in the protasis, though the apodosis contains the pluperfect, see Zumpt, S 525.
"De Bello Catilinario et Jugurthino" by Caius Sallustii Crispi (Sallustius)
Here we regularly have the Indicative in both Protasis and Apodosis.
"New Latin Grammar" by Charles E. Bennett
It consists of two parts, a protasis and an apodosis.
"The Simpkins Plot" by George A. Birmingham
It is the custom of lovers to abuse of the gorgiaques figures from the very protasis and exordium.
"Prairie Farmer, Vol. 56: No. 3, January 19, 1884." by Various
In a sentence with "if," "when," "though," &c., put the "if-clause," antecedent, or protasis, first.
"How to Write Clearly" by Edwin A. Abbott
I will: for the end of the protasis lies yet some way off.
"From a Cornish Window" by Arthur Thomas Quiller-Couch
Padre Protasi, S. J., is dead.
"Donahoe's Magazine, Vol. XV, No. 4, April, 1886" by Various

In science:

As an example of such idea, we only recall the definition of APreduction (Crescenzi, Kann, Protasi, and Trevisan, 1995), that will be used later in this chapter.
Random Generation and Approximate Counting of Combinatorial Structures
The complexity of finding locally optimal solutions for those pr oblems has been mainly investigated by Johnson, Papadimitriou, and Yannakakis (1988); Ausiello and Protasi (1995), showing the strengths and the limits of such a paradigm.
Random Generation and Approximate Counting of Combinatorial Structures
The first definitions of approximation-preserving reductions appear in work by Paz and Moran [PM81] and by Ausiello, D’Atri and Protasi [ADP80].
Inapproximability of Combinatorial Optimization Problems
ACG+ 99] Giorgio Ausiello, Pierluigi Crescenzi, Giorgio Gambosi, Viggo Kann, Alberto Marchetti-Spaccamela, and Marco Protasi.
Inapproximability of Combinatorial Optimization Problems
Protasi, Structure preserving reductions among convex optimization problems, J.
Approximability of Integer Programming with Generalised Constraints