open (adjective)–a reformatting of (source)
from the Old English open means
not closed down, raised up (of gates, eyelids, etc.), also exposed, evident, well-known, public
often in a bad sense,
from the Proto-Germanic
*upana, literally put or set up (source).
as related to an open road
(1817, American English) originally meant a public one; romanticized sense of ‘raveling as an expression of personal freedom’ first recorded 1856, in Whitman.
open, in the early 13c. meant,
an aperture or opening, from (source) adj.
also defined as
public knowledge [as in] out in the open is from 1942, but compare Middle English in open (late 14c.)
Open up means
cease to be secretive from 1921.