More common in older cities like London (Aldgate, Cheapside, Crosswall, Eastcheap, Houndsditch, Lothbury, Minories, Moorgate, Poultry, Queenhithe, St. Mary Axe, and Walbrook, just to name those that merit a Wikipedia article of their own), single-word street names are a rarity in Seattle. NW Esplanade is one of them. It was platted in 1924 as part of the Golden View Addition, and its extension in 1927 as part of the Loyal Heights Annex.
NW Esplanade runs just over half a mile along the Puget Sound shoreline from Triton Drive NW in the northeast to just shy of the northern boundary of Golden Gardens Park in the southwest. For those who might not know, the word means “a long, open, level area, usually next to a river or large body of water where people may walk.”