| rule of three |
the method of finding the fourth term of a mathematical proportion when three terms are given, the product of the first and fourth terms being equal to the product of the second and third. |
| three R's |
reading, writing, and arithmetic, considered as the fundamentals of education. |
| three-base hit |
a hit in baseball that allows the batter to reach third base safely; triple. |
| three-card monte |
a gambling game in which three cards are dealt face down and shuffled about, and spectators then bet on the location of a particular card. |
| three-decker |
something with three levels or layers, esp. a sandwich with three slices of bread; triple-decker. [2 definitions] |
| three-digit number |
a whole number containing three digits, such as 365. |
| three-dimensional |
having or appearing in three dimensions; having depth as well as height and width. [2 definitions] |
| three-four time |
see "three-quarter time." |
| three-mile limit |
the outer limit, under international law, of a country's jurisdiction extending from its coast. |
| three-phase |
of, designating, or pertaining to an electrical circuit, system, or device powered by three alternating electromotive forces that differ in phase by one-third of a cycle, or 120 electrical degrees. |
| three-piece |
made of or having three parts. [2 definitions] |
| three-ply |
having three layers, strands, or the like bonded or woven together. |
| three-point landing |
a perfect aircraft landing in which the two main wheels and the tail or nose wheel touch down simultaneously. |
| three-point play |
in basketball, a play in which a player is fouled while making a two-point basket and then scores another point on the subsequent free throw. |
| three-quarter time |
a musical meter having three quarter notes or their equivalent in each measure; three-four time. |
| three-ring circus |
a circus having simultaneous performances in three separate rings. [2 definitions] |
| three-way |
designed to operate in three ways, esp. as a light bulb or electrical switch that operates on three different wattages. |
| three-wheeler |
a vehicle with three wheels, such as a tricycle or some early or experimental cars. |