OPE
Ope, v. t. & i.
Defn: To open. [Poetic] Wilt thou not ope thy heart to know What rainbows teach and sunsets show Emerson.
OPEIDOSCOPE
O*pei"do*scope, n. Etym: [Gr. -scope.] (Physics)
Defn: An instrument, consisting of a tube having one end open and the other end covered with a thin flexible membrance to the center of which is attached a small mirror. It is used for exhibiting upon a screen, by means of rays reflected from the mirror, the vibratory motions caused by sounds produced at the open end of the tube, as by speaking or singing into it. A. E. Dolbear.
OPELET
Ope"let, n. (Zoöl.)
Defn: A bright-colored European actinian (Anemonia, or Anthea, sulcata); — so called because it does not retract its tentacles.
OPEN O"pen, a. Etym: [AS. open; akin to D. open, OS. opan, G. offan, Icel. opinn, Sw. öppen, Dan. aaben, and perh. to E. up. Cf. Up, and Ope.]
1. Free of access; not shut up; not closed; affording unobstructed ingress or egress; not impeding or preventing passage; not locked up or covered over; — applied to passageways; as, an open door, window, road, etc.; also, to inclosed structures or objects; as, open houses, boxes, baskets, bottles, etc.; also, to means of communication or approach by water or land; as, an open harbor or roadstead. Through the gate, Wide open and unquarded, Satan passed. Milton
Note: Also, figuratively, used of the ways of communication of the
mind, as by the senses; ready to hear, see, etc.; as, to keep one's
eyes and ears open.
His ears are open unto their cry. Ps. xxxiv. 15.
2. Free to be used, enjoyed, visited, or the like; not private; public; unrestricted in use; as, an open library, museum, court, or other assembly; liable to the approach, trespass, or attack of any one; unprotected; exposed. If Demetrius . . . have a matter against any man, the law is open and there are deputies. Acts xix. 33. The service that I truly did his life, Hath left me open to all injuries. Shak.