plural of open set

(topology, mathematical analysis, restricted to metric spaces) The set of all points in a metric space whose distance from a given point ("the open ball's center") is less than a given length ("the open ball's radius").

A romantic and/or sexual relationship in which the people involved are permitted or tolerated to be available to have additional simultaneous romantic and/or sexual relationships.

plural of open relationship

plural of open bite

(hunting, sometimes followed by on or for to designate the kind of animal hunted) A period of time during the calendar year when authorities within a jurisdiction permit the unrestricted hunting of one or more kinds of animal wildlife.

A configuration of a mouth wherein the front top teeth are separated vertically from the front bottom teeth even while the back top teeth are resting directly upon the back bottom teeth.

(phonetics, of a vowel) pronounced with the tongue in a position approximately one-third of the way between an open and a close vowel

(rugby) the portion of the field which is larger as measured from a scrum or breakdown to the touchline

A marital relationship in which each partner agrees that the other partner may have sexual relations with other people as he or she sees fit.