Does “comperendinare” really mean “to adjourn for three days” (or similar) and if yes, how do we know this?

Question

According to my (German) Latin dictionary (Stowasser), comperendinō means to summon for the third-next day of court (für den drittnächsten Gerichtstag vorladen). It always struck me as bizarre that a word should have such a specific meaning.

Other sources I can find online offer the same or similar meanings involving three or more days of adjournment or similar.

I am curious about the following:

• Is that actually correct?
• If yes, how do we know this?
• If yes, do we have any idea why Latin developed a word for such a specific meaning?

Answer 1

Regarding the specific legal proceedings, Ramsay (p. 145):

Comperandinatio.—After the passing of the Lex Servilia (about B.C. 104), the process in trials De Repetundis was altogether peculiar, for at that period Comperendinatio was introduced. By this arrangement, all trials De Repetundis were divided into two distinct parts, Actio Prima and Actio Secunda. In the Actio Prima, the accuser gave an outline of the case; the defender then replied; and the witnesses were examined The proceedings were now suspended until the next day but one (tertio die—perendie, and hence the word Comperendinatio), when the Actio Secunda took place. When this second hearing was concluded, the Jury gave it verdict of condemnation or acquittal, no option left of saying Non Liquet.

Crimes de repetundis are defined thus by Harpers (s.v. repetundae):

Repetundae pecuniae in its widest sense was the term used to designate such sums of money as the socii of the Roman state or individuals claimed to recover from magistratus, judices, or public curatores, which they had improperly taken or received in the Provinciae or in the Urbs Roma, either in the discharge of their jurisdictio, or in their capacity of judices, or in respect of any other public function. Hence the word repetundae came to be used to express the illegal act of officials in extorting or taking money from those subject to them, as in the phrase repetundarum insimulari, damnari;and pecuniae meant not only money, but anything that had value. ...

References

1. William Ramsay. 1859. An Elementary Manual of Roman Antiquities.
2. Harry Thurston Peck. 1898. Harpers Dictionary of Classical Antiquities.

Answer 2

The word comperendinare is related to the adverb perendie (on the day after tomorrow) and means "to postpone until perendie". Starting from a specific word for this day, it does not sound all that weird to have a related verb.

Similarly, the word cras (tomorrow) and the related adjective crastinus give rise to the verb procrastinare (to postpone until tomorrow, to procrastinate). The question arises, of course, why these verbs were derived in this particular manner, but the analogy is clear.

Comperendinare or comperendinatio is mainly a legal term. I cannot explain why adjournment for two days was such an important thing. Perhaps someone else could shed light on the legal side.

As pointed out in the comment, the Romans counted days inclusively. Tomorrow is the second day after today, and the day after tomorrow is the third day after today. Therefore perendie is "three days after today" (most modern people would say two) and so comperendinare corresponds to "adjourning for three days".