bar

Modular segment of music incorporating a fixed number of beats, as in the phrase ‘two/three/four beats to the bar’. It is shown in notation by vertical ‘barring’ of the musical continuum. The US term is measure.

bar

In physics, unit of pressure equal to 105 pascals or 106 dynes/cm2, approximately 750 mmHg or 0.987 atm. Its diminutive, the millibar (one-thousandth of a bar), is commonly used by meteorologists.

bar

In earth sciences, deposit of sand or silt formed in a river channel, or a long ridge of sand or pebbles running parallel to a coastline (see coastal erosion). Coastal bars can extend across estuaries to form bay bars and are formed in one of two ways. Longshore drift can transport material across a bay and deposit it, thereby closing off the bay. Alternatively, an offshore bar (formed where waves touch the seabed and disturb the sediments, causing a small ridge to be formed) may be pushed towards the land as the sea level rises. These bars are greatly affected by the beach cycle. The high tides and high waves of winter erode the beach and deposit the sand as offshore bars. These are known as barrier beaches in the USA.