Etymology of "research"?

The OED says:

Apparently < re- prefix + search n., after Middle French recerche (rare), Middle French, French recherche thorough investigation (1452; a1704 with spec. reference to investigation into intellectual or academic questions; 1815 in plural denoting scholarly research or the published results of this), introductory passage played on a piano or organ (early 18th cent.). Compare Italian ricerca (1470). Compare slightly later research v. 1

So it appears the English was, if not borrowed from the French, at least modelled on it; and the French word already had something like the modern meaning.

Under "re-" the OED says: "The original sense of re- in Latin is ‘back’ or ‘backwards’, but in the large number of words in which it occurs it shows various shades of meaning ... ", but it does not give a meaning specifically which would account for the sense of "rechercher/research"

That article you linked to is interesting. The author of it had already considered the OED definition that Colin cited, but poses two alternative theories about the meaning or history of the word recherche and asks readers to vote. Basically, one theory is that recherche means to search intensely or thoroughly, and one theory is that it means to literally search again.

I think, given that reproducibility is one of the main principles of the scientific method, it is not a far stretch to think research means to search and search again. Scientists do like to think they're doing new-search, as the blog you reference states, but the work (whether an experiment or study) has to be reproduced by someone else working independently.

So if I were to vote on that blog, I'd pick Theory B. I hope someone who knows French might weigh in.

• English: research

  Etymology
  Early Modern French rechercher (“to examine closely”), from Old French recerchier (“to seek, to look for”).

• French: rechercher

  1. to search for, to look for
  2. to search again, to look for again

  Etymology
  Since Middle French, from Old French recerchier, from re- + cerchier (“to look for”). Compare English research and recherche.

• Old French: recerchier

  1. to search; to look for

• Old French: cerchier

  1. to search; to seek; to look for

  Etymology
  From Late Latin circāre, present active infinitive of circō, from Latin circa, circus.

• Old French: re-

  1. re- (again; once more)

• Latin: circō

  1. I traverse, go about
  2. I wander through

  Etymology
  From circus (“circle”) +‎ -ō.

• Latin: re-

  1. back, backwards
  2. again; prefix added to various words to indicate an action being done again, or like the other usages indicated above under English.

  Etymology
  The Latin prefix rĕ- is from Proto-Italic *wre (“again”), which has a parallel in Umbrian re-, but its further etymology is uncertain (OED). While it carries a general sense of "back" or "backwards", its precise sense is not always clear, and its great productivity in classical Latin has the tendency to obscure its original meaning.

Note that "its precise sense is not always clear" and as the blog itself notes, re- can be an intensifier, not just meaning "again".

The change of meaning from "wander" to "search" seems straightforward. Note how Old French cerchier, recerchier (to search) became Modern French rechercher with a dual meaning of to search and to search again.

There was a point in time where intensifiers were very fashionable in French, so much so that they became part of the standard language. For example pas (not) comes from a word literally meaning step, because they would stamp their foot as they were saying it. This is why in standard French there are two words (ne and pas) to negate most sentences:

Je n'aime pas le spam!

I don't like [stomp!] spam!

Just to be clear, modern French people don't stamp their foot when they say "pas"!

It seems reasonable that rechercher (strong-search) became synonymous with chercher (search) until eventually chercher was lost in French. So the etymology of English research looks to me like strong-search, not again-search.