OCTOSYLLABLE
Oc"to*syl`la*ble, n.

Defn: A word of eight syllables.

OCTOYL
Oc"to*yl (, n. Etym: [Octoic + -yl.] (Chem.)

Defn: A hypothetical radical (C8H15O), regarded as the essential residue of octoic acid.

OCTROI
Oc`troi", n. Etym: [F.]

1. A privilege granted by the sovereign authority, as the exclusive right of trade granted to a guild or society; a concession.

2. A tax levied in money or kind at the gate of a French city on articles brought within the walls. [Written also octroy.]

OCTUOR
Oc"tu*or, n. Etym: [From L. octo eight + -uor, as in L. quatuor.]
(Mus.)

Defn: See Octet. [R.]

OCTUPLE
Oc"tu*ple, a. Etym: [L. octuplus; cf. Gr. octuple.]