Tw

Tweeter
A speaker that reproduces only frequencies above a certain range, usually about 3 kHz.
Twenty Four Hour Clock
The convention of time keeping in which the day runs from midnight to midnight and is divided into 24 hours numbered from 0 to 23.
Twin
Two portions of a crystal with a definite orientation relationship.
Twin Bands
Bands across a crystal grain where crystallographic orientations have a mirror image relationship to the orientation of the matrix grain across a composition plane usually parallel to the sides of the band.
Twin Primes
Two prime numbers that differ by 2. eg 11 and 13.
Twist Drill
A commonly used metal-cutting drill, usually made with two flutes running around the body.
Twisted Pair
Cable that consists of individual wires wrapped around each other for carrying telephone or computer data.
Two Body Problem
Classical celestial mechanics which treats of the relative motion of two point masses under their mutual gravitational attraction.
Two Colour Thermometry
A technique that measures the energy in two different wavelength bands in order to determine temperature.
Two Dimensional
Having both width and length, but no thickness.
Two Electrode Cell
A classical electrochemical cell containing two electrodes.
Two Man Crosscut Saw
A saw with a handle for a man at each end.
Two Position Valve
A valve which is either fully on or fully off with no positions between.
Two Wire Open Line
A parallel line consisting of two wires that are generally spaced from 50 to 150mm apart by insulating spacers.
Two Wire Ribbon
A parallel two-wire line in which uniform spacing is assured by two wires imbedded in a low-loss dielectric.
Two-Stroke Engine
An internal-combustion engine that has one power stroke per revolution.
Two-Way Valve
Valve with one inlet port and one outlet port.