1. on the inner side or part of; within: inside the circle; inside the envelope.2. prior to the elapse of; within: He promised to arrive inside an hour.adv.3. in or into the inner part: Please go inside.4. indoors: They play inside on rainy days.5. within one's heart, reason, etc.; by true nature; basically: I know inside that he's not guilty. Inside, she's really very shy.6. Slang. in prison.7. inside of, Informal. within the space or period of: Our car broke down again inside of a mile.n.8. the inner or internal part; interior: the inside of the house.9. the inner side or surface: the inside of the hand; He pinned the money to the inside of his jacket.10. Usually, insides. Informal. the inner parts of the body, esp. the stomach and intestines: The coffee scalded my insides.11. a select or inner circle of power, prestige, etc.: a man on the inside.12. the shortest of several parallel, curving tracks or lanes; the part of an oval track closest to the inner rail: The horse came up fast on the inside.13. the inward nature, mind, feelings, etc.14. Slang. confidential or secret information.15. an inside passenger or place in a coach, carriage, etc.16. inside out,a. with the inner side reversed to face the outside.b. thoroughly; completely: She knew the work inside out.adj.17. situated or being on or in the inside; interior; internal: an inside seat.18. acting, employed, done, or originating within a building or place: He used to work on the dock but now he has an inside job.19. derived from the inner circle of those concerned in and having private knowledge of a situation: inside information.20. Baseball. (of a pitched ball) passing between home plate and the batter: The pitch was low and inside.[1350-1400; ME; see IN, SIDE1]Syn. 8. INSIDE, INTERIOR both refer to the inner part or space within something. INSIDE is a common word, and is used with reference to things of any size, small or large: the inside of a pocket. INTERIOR, somewhat more formal, denotes the inner part or the space or regions within; it usually suggests considerable size or extent, and sometimes a richness of decoration: the interior of a country, of the earth, of a cathedral.Ant. 8. outside, exterior.
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