Seesaw a "teeter-totter". According to linguist Peter Trudgill, the term originates from the Nordic language word "tittermatorter". A "teeter-totter" may also refer to a two-person swing on a swing seat, on which two children sit facing each other and the teeter-totter swings back and forth in a pendulum motion. Both "teeter-totter" (from "teeter", as in "to teeter on the edge") and "seesaw" (from the verb "saw") demonstrate the linguistic process called reduplication, where a word or syllable is doubled, often with a different vowel. Reduplication is typical of words that indicate repeated activity, such as riding up and down on a
Time synchronization in North America Time synchronization in North America Time synchronization in North America can be achieved with many different methods, some of which require only a telephone, while others require expensive, sensitive, and rare electronic equipment. In the United States, the United States Naval Observatory provides the Standard of Time, called UTC(USNO), for the United States military and the Global Positioning System, while the National Institute of Standards and Technology provides the Standard of Time for civil purposes in the United States, called UTC(NIST). A Standard frequency and time signal service is a station that operates on or immediately adjacent to 2.5 MHz,