Replenishment oiler in the context of "INS Deepak"

A tanker (or tank ship or tankship) is a ship designed to transport or store liquids or gases in bulk. Major types of tanker ship include the oil tanker (or petroleum tanker), the chemical tanker, cargo ships, and a gas carrier. Tankers also carry commodities such as vegetable oils, molasses and wine.

In the United States Navy and Military Sealift Command, a tanker used to refuel other ships is called an oiler (or replenishment oiler if it can also supply dry stores) but many other navies use the terms tanker and replenishment tanker.

A carrier strike group (CSG) is a type of carrier battle group of the United States Navy. It is an operational formation composed of roughly 7,500 personnel, usually an aircraft carrier, at least one cruiser, a destroyer squadron of at least two destroyers or frigates, and a carrier air wing of 65 to 70 aircraft. A carrier strike group also, on occasion, includes submarines, attached logistics ships and a supply ship. The carrier strike group commander operationally reports to the commander of the numbered fleet, who is operationally responsible for the area of waters in which the carrier strike group is operating.

Strike groups comprise a principal element of U.S. power projection capability; a single supercarrier holds enough firepower to rival the air forces of entire nations. Previously referred to as carrier battle groups (a term still used by other nations), they are often referred to by the carrier they are associated with (e.g., Enterprise Strike Group). As of March 2023 there are 11 carrier strike groups in the U.S. Navy.