Defn: An order of eellike fishes having the scapular arch attached to the vertebræ, but not connected with the skull.

OPISTHOPULMONATE
O*pis`tho*pul"mo*nate, a.Etym: [Gr. pulmonate.] (Zoöl.)

Defn: Having the pulmonary sac situated posteriorly; — said of certain air-breathing Mollusca.

OPISTHOTIC
Op`is*thot"ic, n. Etym: [Gr. (Anat.)

Defn: The inferior and posterior of the three elements forming the periotic bone.

OPISTHOTONOS
Op`is*thot"o*nos, n. Etym: [NL., from Gr. (Med.)

Defn: A tetanic spasm in which the body is bent backwards and stiffened.

OPITULATION O*pit`u*la"tion, n. Etym: [L. opitulatio, fr. opitulari to bring help.]

Defn: The act of helping or aiding; help. [Obs.] Bailey.

OPIUM
O"pi*um, n. Etym: [L., fr. Gr. (Chem.)