round

round, in music, a perpetual canon on a tune that returns to its beginning in which all the voices enter at the unison or the octave. An example is Sumer Is Icumen In. Rounds were popular in 17th-century England when the catch reached its height. The catch was originally just a simple round, e.g., Three Blind Mice, written in a single line with the effect gained by having another singer come in ("make the catch") at the right time. Later, comic effects, often quite bawdy, were added, using the interweaving of the parts. The Rounds, Catches and Canons of England (1864) by E. F. Rimbault is a comprehensive collection. The term round was also used to designate a dance performed in a circle and, by extension, to the tunes for such dances.

or arena stage

Theatre in which the stage is located in the centre of the auditorium with the audience seated on all sides. The form evolved from Greek theatre and was used in medieval times. From the 17th century the proscenium stage limited audience seating to the area directly in front of the stage. In the 1930s, plays at Moscow's Realistic Theatre were produced in the round and the arena stage began to gain favour in Europe and the U.S. Its advantages are its informality and the rapport it creates between audience and actors, but it requires actors to turn constantly to address new sections of the audience.

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or roundworm

Any of more than 15,000 named and many more unnamed species of worms in the class Nematoda (phylum Aschelminthes). Nematodes include plant and animal parasites and free-living forms found in soil, freshwater, saltwater, and even vinegar and beer malts. They are bilaterally symmetrical and usually tapered at both ends. Some species have separate sexes; others are hermaphroditic. They range from microscopic to about 23 ft (7 m) long. Nematode parasites can occur in almost any body organ but are most common in the digestive, circulatory, or respiratory system. Hookworms, pinworms, and eelworms are nematodes. Seealso filarial worm, guinea worm, trichina.

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English round, or simple perpetual canon, for three or more unaccompanied voices. Catches were sung by men as a popular pastime in the 16th–19th centuries. Catch texts were often humorous or ribald, and in some instances a pause in the melody in one voice was filled in by the notes and text of another, creating a pun or change of meaning, especially in the late-17th-century Restoration period.

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In telecommunications, the term round-trip delay time or round-trip time (RTT) has the following meanings:

1. The elapsed time for transit of a signal over a closed circuit, or time elapsed for a message to a remote place and back again.
2. In primary or secondary radar systems, the time required for a transmitted pulse to reach a target and for the echo or transponder reply to return to the receiver.

Round-trip delay time is significant in systems that require two-way "interactive" communication, such as voice telephony, or ACK/NAK data systems where the round-trip time directly affects the throughput rate, such as the Transmission Control Protocol (TCP). It may range from a very few microseconds for a short line-of-sight (LOS) radio system to many seconds for a multiple-link circuit with one or more satellite links involved. This includes the node delays as well as the media transit time.

In regards to TCP communication the RTT time is calculated from the 3-way handshake by measuring the time between segment transmission and ACK receipt.