purview

First recorded in 1225–75; Middle English purveu, from Anglo-French: past participle of purveier “to furnish or supply”; see origin at purvey

Purview comes from Anglo-French purveu, purveue, porveu (with other spelling variants) in the legal phrase purveu est (ke) “it is provided (that)” or purveu que “provided that.” The phrase occurs at or near the beginning of a statute or other legal document. The original (legal) sense “a provisional or qualifying clause; proviso” is now obsolete.
Purveu is the past participle of the verb porveeir, porveoir, purveer (and other variants) “to make available, provide, purvey,” from Latin prōvidēre “to see in advance, look ahead, take precautions, provide for, take measures.”
The current English spelling purview is due to the influence of view, itself from Anglo-French vew, vewe, vieu, vieue, view, ultimately from Vulgar Latin vidūta, the past participle of vidēre “to see.” Around the same time that we see the spelling purview, a metaphorical sense arose, “the range of operation, authority, control, concern, etc.,” a direct extension of the original sense. From this developed a more literal sense related to seeing, “the range of vision, insight, or understanding.”