mindmap root((METR/METER)) metric 1、 Relating to or based on the metric system.
2、 Relating to or arranged in meter.
🌱Americans have resisted using the metric system for years, but are now slowly getting accustomed to a few of the metric units. 🌳The metric system was invented in France in the years following the French Revolution, and a version of it is now used in most of the world to measure distance, weight, and volume. Basic metric units include the kilogram （the basic unit of weight）, the liter （the basic unit of volume）, and of course the meter （the basic unit of length—see below）. Metric—or more often metrical—can also refer to the basic underlying rhythm of songs and poetry. So while the scientists' measurements are usually metric, the poets' are usually metrical. meter 1、 The basic metric unit of length, equal to about 39.37 inches.
2、 A systematic rhythm in poetry or music.
🌱The basic meter of the piece was 3/4, but its rhythms were so complicated that the 3/4 was sometimes hard to hear. 🌳Meter is a metric measurement slightly longer than a yard; thus, a 100-meter dash might take you a second longer than a 100-yard dash. But the word has a different sense in music, where people aren't separated by whether they use the metric system. For a musician, the meter is the regular background rhythm, expressed by the "time signature" written at the beginning of a piece or section: 2/2, 2/4, 3/8, 4/4, 6/8, etc. Within a meter, you can create rhythms that range from the simple to the complex. So, for example, "America the Beautiful" is in 4/4 meter （or "4/4 time"）, but so are most of the rhythmically complex songs written by Paul Simon, Burt Bacharach, or Stevie Wonder. In ordinary conversation, though, most people use "rhythm" to include meter and everything that's built on top of it. In poetry, meter has much the same meaning; however, poetic meters aren't named with numbers but instead with traditional Greek and Latin terms such as iambic and dactylic. odometer An instrument used to measure distance traveled.
🌱Jennifer watched the odometer to see how far she would have to drive to her new job. 🌳Odometer includes the root from the Greek word hodos, meaning "road" or "trip." An odometer shares space on your dashboard with a speedometer, a tachometer, and maybe a "tripmeter." The odometer is what crooked car salesmen tamper with when they want to reduce the mileage a car registers as having traveled. One of life's little pleasures is watching the odometer as all the numbers change at the same time. tachometer A device used to measure speed of rotation.
🌱Even though one purpose of a tachometer is to help drivers keep their engine speeds down, some of us occasionally try to see how high we can make the needle go. 🌳A tachometer is literally a "speed-measurer," since the Greek root tach- means "speed." This is clear in the names of the tachyon, a particle of matter that travels faster than the speed of light （if it actually exists, it's so fast that it's impossible to see with any instrument）, and tachycardia, a medical condition in which the heart races uncontrollably. Since the speed that an auto tachometer measures is speed of rotation of the crankshaft, the numbers it reports are revolutions per minute, or rpm's.