Envelope
来自Big Physics
mid 16th century (in the sense ‘wrapper, enveloping layer’; originally as envelope ): from French enveloppe, from envelopper ‘envelop’. The sense ‘covering of a letter’ dates from the early 18th century.
wiktionary
From French enveloppe.
See envelop.
etymonline
envelope (n.)
"a wrapper, an enclosing cover," specifically a prepared wrapper for a letter or other paper, 1705, from French enveloppe (13c.), a back-formation from envelopper "to envelop" (see envelop).
