in·side • n. / ˈinˈsīd/ 1. [usu. in sing.] the inner side or surface of a thing: she ran a finger around the inside of the bowl. ∎  the side of a bend or curve where the edge or surface is shorter: the inside of the bend. ∎  the side of a racetrack nearer to the center, where the lanes are shorter: he was blocked on the inside at the furlong marker.2. the inner part; the interior: the inside of the car was like an oven these boats are built of very thin cedar, with ribs on the inside. ∎  (usu. insides) inf. the stomach and bowels: my insides are out of order.3. (the inside) inf. a position affording private information: will you be my spy on the inside?• adj. / ˌinˈsīd; ˈinˌsīd/ situated on or in, or derived from, the inside: an inside pocket. ∎  (in some team sports) denoting positions nearer to the center of the field: possibly the best inside linebacker in the country. ∎  (in basketball) taking place within the perimeter of the defense: he missed three consecutive inside shots. ∎  (of a pitch in baseball) passing between the batter and the strike zone: an inside pitch to a right-handed hitter.• prep. & adv. / ˌinˈsīd/ 1. situated within the confines of (something): [as prep.] a radio was playing inside the apartment he fitted a light inside the cupboard | [as adv.] Mr. Jackson is waiting for you inside. ∎  moving so as to end up within (something): [as prep.] Anatoly reached inside his shirt and brought out a map | [as adv.] we walked inside. ∎  [adv.] indoors: they sat inside playing cards. ∎  within (the body or mind of a person), typically with reference to sensations of self-awareness: [as prep.] she felt a stirring of life inside her I just roll the phrases around inside my head | [as adv.] I was screaming inside. ∎ inf. in prison: sentenced to three years inside. ∎  Baseball close to the batter. ∎  (in basketball, soccer, and other sports) closer to the center of the field than (another player): [as prep.] he went inside Graves and scored near the post | [as adv.] he does an excellent job of getting the ball inside to Randall. 2. [prep.] in less than (the period of time specified): the oven will have paid for itself inside 18 months.PHRASES: inside of inf. within: something inside of me wanted to believe him. ∎  in less than (the period of time specified): rerigging a ship for a voyage inside of a week.