A slang term for calibration (a setting of all operating controls and adjustments for optimum performance of a device) especially very precise calibration.
Found on http://www.encyclo.co.uk/local/20447
• (n.) Trouble; distress; tweag. • (v. t.) To pinch and pull with a sudden jerk and twist; to twitch; as, to tweak the nose. • (n.) A sharp pinch or jerk; a twist or twitch; as, a tweak of the nose. • (n.) A prostitute. Found on http://thinkexist.com/dictionary/meaning/tweak/