плацда́рм meaning in English — beachhead, bridgehead, foothold

English meaning

beachhead noun A secured area on an enemy shoreline used to bring in more troops and supplies during an invasion.
bridgehead noun An area around the end of a bridge.
foothold noun A secure place to put one's foot when climbing.
springboard noun A flexible board used to launch a diver or gymnast into the air.

плацда́рм is used for these senses in English:

beachhead (military) An area of hostile territory (especially on a beach) that, when captured, serves for the continuous landing (or movement into position) of further troops and material
bridgehead (military) An area of ground on the enemy's side of a river or other obstacle, especially one that needs to be taken and defended in order to secure an advance.
bridgehead (physical chemistry) Either of the two atoms in different parts of a molecule that are connected by a bridge of two or more other atoms
foothold (military) Airhead, beachhead, bridgehead, lodgement.
parade ground (military) A large area of firm ground, formerly usually adjacent to fortifications and now usually a paved area at a military base, where soldiers present themselves for inspection ("parade") and practice marching and close-order drills.
springboard (figuratively) Something that acts as a catalyst to begin or accelerate an action or growth.
stepping stone (idiomatic) Something used as a way to progress to something or somewhere else.

noun A secured area on an enemy shoreline used to bring in more troops and supplies during an invasion.
noun An initial foothold or early success that makes further progress possible.

noun An area around the end of a bridge.
noun A fortification around the end of a bridge.
noun An area of ground on the enemy's side of a river or other obstacle, especially one that needs to be taken and defended in order to secure an advance.
noun Either of the two atoms in different parts of a molecule that are connected by a bridge of two or more other atoms