esplanade
Synonym discussion
Sense: noun/1
For noun/1, esplanade is closest to promenade because both name a broad place for walking in an open public setting, often by the sea. Esplanade usually suggests a wider, more built-up strip beside water or a large open edge, while promenade often puts more focus on the relaxed act of strolling. Boardwalk is narrower in meaning because it normally means a wooden walkway, especially at a beach. Walkway is the plain everyday word and can describe any path for pedestrians, not necessarily a scenic public one. Boulevard is different because it is mainly a road, even if people can walk beside it. You can stroll along an esplanade at sunset, but you would cross a walkway to reach the station.
Etymology
Esplanade came into English through French and originally referred to ground that had been made flat and open. That earlier military sense later widened into the modern idea of a broad open place or public walk, especially one beside the sea or a river where people can stroll easily.