1570s, "act of searching closely" for a specific person or thing, from French recerche (1530s, Modern French recherche), back-formation from Old French recercher "seek out, search closely" (see research (v.)).
The meaning "diligent scientific inquiry and investigation directed to the discovery of some fact" is attested by 1630s. The general sense of "investigations into things, the habit of making close investigations" is by 1690s. The phrase research and development for "work on a large scale toward innovation" is recorded from 1923.
1590s, "investigate or study (a matter) closely, search or examine with continued care," from French recercher, from Old French recercher "seek out, search closely," from re-, here perhaps an intensive prefix (see re-), + cercher "to seek for," from Latin circare "go about, wander, traverse," in Late Latin "to wander hither and thither," from circus "circle" (see circus).
The intransitive meaning "make researches" is by 1781. Sometimes 17c. also "to seek (a woman) in love or marriage." Related: Researched; researching.
"investigator, inquirer, one who makes researches," 1610s, agent noun from research (v.).
"one eminent for learning," especially one engaged in scientific or learned research, 1719, from French savant "a learned man," noun use of adjective savant "learned, knowing," the former present participle of savoir "to know" (modern French sachant), from Vulgar Latin *sapere, from Latin sapere "be wise" (see sapient).