Treble describes tones of high frequency or high pitch, ranging from 6kHz to 20kHz, comprising the higher end of the human hearing range. In music, this corresponds to high notes.

A treble in association football is achieved when a club team wins three trophies in a single season. A continental treble involves winning the club's national league competition, main national cup competition, and main continental trophy.

Arthur Leonard Treble (8 October 1889 – 1 September 1966) was a British track and field athlete who competed in the 1912 Summer Olympics in Stockholm, Sweden. He was born in Chichester.

The alto recorder in F, also known as a treble (and, historically, as consort flute and common flute) is a member of the recorder family. Up until the 17th century the alto instrument was normally in G4 instead of F4.

In mathematics and group theory, a block system for the action of a group G on a set X is a partition of X that is G-invariant. In terms of the associated equivalence relation on X, G-invariance means that

A system of signalling on railroads. The essence of the system consists in having signal posts or stations all along the road at distances depending on the traffic. The space between each two signal posts is termed a block. From the signal posts the trains in day time are signalled by wooden arms termed semaphores, and at night by lanterns. The arms may be moved by hand or by automatic mechanism depending in part on electricity for carrying out its functions. Thus in the Westinghouse system the semaphores are moved by pneumatic cylinders and pistons, whose air valves are opened and shut by the action of solenoid magnets, q. v. The current of these magnets is short circuited by passing trains, so as to let the valves close as the train passes the signal post. The block system causes the semaphore to be set at "danger" or "caution," as the train enters the next block. Then the following train is not allowed to enter the block until the safety signal is shown. The Westinghouse system provides for two semaphores on a post, one indicating "danger" as long as the train is on the next block; the other indicating "caution" as long as the train is on the next two blocks. The rails form part of the circuit, their joints being bridged by copper wire throughout the block, and being insulated where the blocks meet.

Atrioventricular block (AV block) is a type of heart block that occurs when the electrical signal traveling from the atria, or the upper chambers of the heart, to ventricles, or the lower chambers of the heart, is impaired. Normally, the sinoatrial node (SA node) produces an electrical signal to control the heart rate.

In cryptography, a block cipher is a deterministic algorithm operating on fixed-length groups of bits, called blocks. They are specified elementary components in the design of many cryptographic protocols and are widely used to encrypt large amounts of data, including in data exchange protocols. It uses blocks as an unvarying transformation.