1. Not closed; exposed, said of a wound. 2. To enter or expose, as a wound or cavity. [A.S.]

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open 'ō-pən adj
1 a) not covered, enclosed, or scabbed over <an \open lesion> <an \open running ulcer>
b) not involving or encouraging a covering (as by bandages or overgrowth of tissue) or enclosure <\open treatment of burns>
c) relating to or being a compound fracture
d) being an operation or surgical procedure in which an incision is made such that the tissues and organs are fully exposed compare OPEN-HEART
2) shedding the infective agent to the exterior <\open tuberculosis> compare CLOSED (3)
3 a) unobstructed by congestion or occlusion <\open sinuses>
b) not constipated <\open bowels>
4) using a minimum of physical restrictions and custodial restraints on the freedom of movement of the patients or inmates <an \open psychiatric ward>
open vb, opened; open·ing vt
1 a) to make available for entry or passage by removing (as a cover) or clearing away (as an obstruction)
b) to free (a body passage) of congestion or occlusion <an inhalator for \opening congested nasal passages> <\open clogged arteries>
2) to make one or more openings in <\opened the boil> vi to spread out <the wound \opened>

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(oґpən) 1. exposed to the air; not covered by unbroken skin. 2. interrupted (as a circuit) so that an electric current cannot pass. 3. not obstructed or closed. 4. pertaining to a clinical trial or other experiment that is not blind; i.e., the subjects and the persons administering the test know which treatment is administered to which subject.

Medical dictionary. 2011.