Lieutenant (abbreviated Lt, LT, LT(N), Lieut and LEUT) is a commissioned officer rank in many nations' navies. It is typically the most senior of junior officer ranks. The rank's insignia usually consists of two medium gold braid stripes and often the uppermost stripe features a loop or executive curl.

The now immediately senior rank of lieutenant commander was formerly a senior naval lieutenant rank. Many navies also use a subordinate rank of sub-lieutenant. The appointment of "first lieutenant" in many navies is held by a senior lieutenant.

Since at least 1580 the lieutenants in a ship had been the officers immediately subordinate to the captain. Before the English Restoration lieutenants were appointed by their captains, and this inevitably led to abuses and to the widespread appointment of men of insufficient qualification. In 1677 Samuel Pepys introduced the first examination for lieutenant, and it is from the date of this examination that their seniority was set.

Lieutenants were numbered by their seniority within the ship, so that a frigate which was entitled to three would have a first lieutenant, a second lieutenant, and a third lieutenant. A first-rate was entitled to six, and they were numbered accordingly. At first a lieutenant's commission was given only for the ship in which he served, but after the loss of HMS Wager in 1741 and the subsequent mutiny, lieutenants were given full commissions upon passing their examination.

A lieutenant (abbreviated Lt, LT, Lieut and LEUT) is a junior commissioned officer in many nations' armed forces. Typically, the rank of lieutenant in naval usage, while still a junior officer rank, is senior to the army rank. It is also used in fire services, emergency medical services, security services and police forces as a rank.

Lieutenant may also appear as part of a title used in various other organizations with a codified command structure. It often designates someone who is "second-in-command," and as such, may precede the name of the rank directly above it. For example, a "lieutenant master" is likely to be second-in-command to the "master" in an organization utilizing both such ranks. Notable uses include lieutenant governor in various governments, and Quebec lieutenant in Canadian politics.

The word lieutenant derives from French; the lieu meaning "in place" as in a position (cf. in lieu of); and tenant meaning "holding" as in "holding a position"; thus a "lieutenant" is somebody who holds a position in the absence of his or her superior (compare the Latin locum tenens). Similar words in other languages include the Arabic mulāzim (Arabic: ملازم‎), meaning "holding a place", and the Hebrew word segen (Hebrew: סגן‎), meaning "deputy" or "second to".

A navy (sometimes called a maritime force) is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake- or ocean-borne combat operations and related functions. It includes anything conducted by surface ships, amphibious ships, submarines, and seaborne aviation, as well as ancillary support, communications, training, and other fields; recent developments have included space-related operations. The strategic offensive role of a navy is projection of force into areas beyond a country's shores (for example, to protect sea-lanes, ferry troops, or attack other navies, ports, or shore installations). The strategic defensive purpose of a navy is to frustrate seaborne projection-of-force by enemies. The strategic task of the navy also may incorporate nuclear deterrence by use of nuclear missiles.

First attested in English c.1600, the word "navy" came via Old French navie, "fleet of ships", from the Latin navigium, "a vessel, a ship, bark, boat", from navis, "ship" and from Sanskrit "नाव" (Nau), "ship".^{[dead link][citation needed]} The word "naval" came from Latin navalis, "pertaining to ship";^{[dead link]} cf. Greek "ναῦς" (naus), "ship", "ναύτης" (nautes), "seaman, sailor" (the earliest attested reference to the word is the Mycenaean Greek na-u-do-mo, "shipbuilders", written in Linear B syllabic script).

Katherine Bailey (born 13 February 1982 in Sydney, New South Wales) is a Paralympic swimming competitor from Australia.

She competed in seven events and won two bronze medals at the 2000 Sydney Games in the women's 100 m butterfly S9 and women's 4x100 m medley 34 pts events.. At the 2004 Athens Games, she competed in four events and repeated her medal results from Sydney winning two bronze medals at the 2000 Sydney Games in the women's 100 m butterfly S9 and women's 4x100 m medley 34 pts events She competed at the 2002 Commonwealth Games in Manchester, England in elite athlete with a disability swimming events. At the 2002 IPC Swimming World Championships in Mar Del Plata, Argentina she won three gold medals.

She was coached by Graeme 'Grub' Carroll at the Warringah Aquatic Swim Club.. From 2002 to 2004 she was an Australian Institute of Sport paralympic swimming scholarship holder. Also she was an New South Wales Institute of Sport scholarship holder.

Lt. Michael Patrick Murphy (May 7, 1976 – June 28, 2005) was a United States Navy SEAL posthumously awarded the United States military's highest decoration, the Medal of Honor, for his actions in 2005 during the War in Afghanistan. He was the first person to be awarded the medal for actions in Afghanistan; and the first member of the U.S. Navy to receive the award since the Vietnam War.

Michael Murphy was born and raised in Suffolk County, New York. After graduating from high school he went to Penn State, graduating with honors and dual degrees in both political science and psychology. After college he accepted a commission in the United States Navy and became a United States Navy SEAL in July 2002.

Murphy was sent on several missions while participating in the Global War on Terrorism and was killed on June 28, 2005 after his team was compromised and surrounded by Taliban forces near Asadabad, Afghanistan.

In addition to the Medal of Honor, Murphy received other awards including the Silver Star and Purple Heart. Since his death, a United States Navy destroyer, a post office, a combat training pool at Naval Station Newport, and a park have been named in his honor.