Main Difference
The main difference between Jetty and Pier is that the Jetty is a low bank stretching from the shore into a water span and Pier is a raised structure in a body of water, typically supported by well-spaced piles or pillars.
Jetty
A jetty is a structure that projects from the land out into water. Often, “jetty” refers to a walkway accessing the centre of an enclosed waterbody. The term is derived from the French word jetée, “thrown”, and signifies something thrown out.
Pier
A pier is a raised structure in a body of water, typically supported by well-spaced piles or pillars. Bridges, buildings, and walkways may all be supported by piers. Their open structure allows tides and currents to flow relatively unhindered, whereas the more solid foundations of a quay or the closely spaced piles of a wharf can act as a breakwater, and are consequently more liable to silting. Piers can range in size and complexity from a simple lightweight wooden structure to major structures extended over 1600 metres. In American English, a pier may be synonymous with a dock.
Piers have been built for several purposes, and because these different purposes have distinct regional variances, the term pier tends to have different nuances of meaning in different parts of the world. Thus in North America and Australia, where many ports were, until recently, built on the multiple pier model, the term tends to imply a current or former cargo-handling facility. In Europe in contrast, where ports more often use basins and river-side quays than piers, the term is principally associated with the image of a Victorian cast iron pleasure pier. However, the earliest piers pre-date the Victorian age.
Jetty (noun)
A structure of wood or stone extended into the sea to influence the current or tide, or to protect a harbor or beach.
Jetty (noun)
A wharf or dock extending from the shore.
Jetty (noun)
A part of a building that jets or projects beyond the rest, and overhangs the wall below.
Jetty (verb)
To jut out; to project.
Jetty (adjective)
Made of jet, or like jet in color.
Pier (noun)
A raised platform built from the shore out over water, supported on piles; used to secure, or provide access to shipping; a jetty.
Pier (noun)
A similar structure, especially at a seaside resort, used to provide entertainment.
Pier (noun)
A structure that projects tangentially from the shoreline to accommodate ships; often double-sided.
Pier (noun)
A structure supporting the junction between two spans of a bridge.
Pier (noun)
A rectangular pillar, or similar structure, that supports an arch, wall or roof.
Jetty (noun)
a landing stage or small pier at which boats can dock or be moored
“Ben jumped ashore and tied the rowboat up to the small wooden jetty”
Jetty (noun)
a bridge or staircase used by passengers boarding an aircraft
“aircraft will not be connected to passenger jetties during maintenance”
Jetty (noun)
a breakwater constructed to protect or defend a harbour, stretch of coast, or riverbank
“engineers constructed jetties in the river to control erosion”