Origin and history of emerge

1630s, "to plunge or sink in" (to something), a sense now obsolete, from Latin mergere "to dip, dip in, immerse, plunge," probably rhotacized from *mezgo, from PIE *mezgo- "to dip, to sink, to wash, to plunge" (source also of Sanskrit majjanti "to sink, dive under," Lithuanian mazgoju, mazgoti, Latvian mazgat "to wash").

Intransitive meaning "sink or disappear into something else, be swallowed up, lose identity" is from 1726, in the specific legal sense of "absorb an estate, contract, etc. into another." Transitive sense of "cause to be absorbed or to disappear in something else" is from 1728. Related: Merged; merging. As a noun, from 1805.

1640s, "unforeseen occurrence, sudden change of condition," from French émergence, from emerger, from Latin emergere "rise up" (see emerge). The oldest English sense is now that of emergency (q.v.) and is obsolete in this word. The surviving meaning "an emerging, process of coming forth" (from concealment or obscurity) is attested by 1704 in astronomy and optics, in general use by 1755, perhaps directly from emerge. In reference to the rising of land from the water in geology, etc., by 1833.