Definitions:
allowing access, passage, or a view through an empty space; not closed or blocked

exposed to the air or to view; not covered

with the outer edges or sides drawn away from each other; unfolded or spread out

(of a business, place of entertainment, etc.) admitting customers or visitors; available for business

freely available or accessible; unrestricted

not concealing one's thoughts or feelings; frank and communicative

(of a matter or decision) not finally settled; still admitting of debate

(of a string) allowed to vibrate along its whole length.

(of a vowel) produced with a relatively wide opening of the mouth and the tongue kept low.

(of an electric circuit) having a break in the conducting path.

move (a door or window) so as to leave a space allowing access and vision

unfold or be unfolded; spread out

make formally ready for customers, visitors, or business

formally establish or begin (a new business or enterprise)

make (something) present, available, or accessible

(of a piece of writing or music) begin

break the conducting path of (an electric circuit)

outdoors, especially in an exposed or unprotected setting

a championship or competition with no restrictions on who may compete

an accidental break in the conducting path for an electric current.