Opal, ō′pal, n. a precious stone of a milky hue, remarkable for its changing colours.—n. Opalesc′ence.—adjs. Opalesc′ent, reflecting a milky or pearly light from the interior; O′paline, relating to, or like, opal.—v.t. O′palise. [Fr. opale—L. opalus.]
Opaque, ō-pāk′, adj. shady: dark: that cannot be seen through: not transparent.—adv. Opaque′ly.—n. Opaque′ness, quality of being opaque: want of transparency. [Fr.,—L. opacus.]
Ope, ōp, v.t. and v.i. (poet.) short for open.
Opeidocope, ō-pī′dō-skōp, n. an instrument for illustrating sound by means of light.
Open, ō′pn, adj. not shut: allowing one to pass out or in: free from trees: not fenced: not drawn together: spread out: not frozen up: not frosty: free to be used, &c.: public: without reserve: frank: easily understood: generous: liberal: clear: unbalanced, as an account: attentive: free to be discussed.—v.t. to make open: to remove hinderances: to bring to view: to explain: to begin.—v.i. to become open: to unclose: to be unclosed: to begin to appear: to begin.—n. a clear space.—n. O′pener.—adjs. O′pen-eyed (Shak.), watchful; O′pen-hand′ed, with an open hand: generous: liberal.—n. O′pen-hand′edness.—adj. O′pen-heart′ed, with an open heart: frank: generous.—ns. O′pen-heart′edness, liberality: generosity: frankness: candour; O′pening, an open place: a breach: an aperture: beginning: first appearance: opportunity.—adv. O′penly.—adj. O′pen-mind′ed, free from prejudice: ready to receive and consider new ideas.—n. O′pen-mind′edness.—adj. O′pen-mouthed, gaping: greedy: clamorous.—ns. O′penness; O′pen-ses′ame, a form of words which makes barriers fly open—from the story of Ali Baba and the Forty Thieves in the Arabian Nights' Entertainments; O′pen-steek (Scot.), a kind of open-work stitching; O′pen-work, any work showing openings through it for ornament.—adj. open-cast, of mining work in open air.—Open verdict (see Verdict). [A.S. open—up, up; cf. Dut. open—op, Ice. opinn—upp, and Ger. offen—auf.]
Opera, op′ėr-a, n. a musical drama: a place where operas are performed.—adj. used in or for an opera, as an opera-glass, &c.—ns. Op′era-cloak, a cloak of elegant form and material for carrying into the auditorium of a theatre or opera-house as a protection against draughts; Op′era-danc′er, one who dances in ballets introduced into operas; Op′era-glass, a small glass or telescope for use at operas, theatres, &c.; Op′era-hat, a hat which can be made flat by compression and expanded again to its full size; Op′era-house, a theatre where operas are represented; Op′era-sing′er.—adjs. Operat′ic, -al, pertaining to or resembling the opera. [It.,—L. opera. Cf. Operate.]
Opera-bouffe, op′ėr-a-bōōf, n. a comic opera. [Fr.,—It. opera-buffa. Cf. Buffoon.]
Operate, op′ėr-āt, v.i. to work: to exert strength: to produce any effect: to exert moral power: (med.) to take effect upon the human system: (surg.) to perform some unusual act upon the body with the hand or an instrument.—v.t. to effect: to produce by agency.—n. Operam′eter, an instrument for indicating the number of movements made by a part of a machine.—adj. Op′erant, operative.—n. an operator.—n. Operā′tion, art or process of operating, or of being at work: that which is done or carried out: agency: influence: method of working: action or movements: surgical performance.—adj. Op′erātive, having the power of operating or acting: exerting force: producing effects: efficacious.—n. a workman in a manufactory: a labourer.—adv. Op′erātively.—ns. Op′erātiveness; Op′erātor, one who, or that which, operates or produces an effect: (math.) a letter, &c., signifying an operation to be performed. [L. operāri, -ātus—opera, work, closely conn. with opus, operis, work.]
Operculum, ō-pėr′kū-lum, n. (bot.) a cover or lid: (zool.) the plate over the entrance of a shell: the apparatus which protects the gills of fishes:—pl. Oper′cula.—adjs. Oper′cular, belonging to the operculum; Oper′culate, -d, having an operculum; Operculif′erous; Oper′culiform; Operculig′enous; Operculig′erous. [L.,—operīre, to cover.]
Operetta, op-ėr-et′a, n. a short, light musical drama. [It., dim. of opera.]