The Adam brothers built a very large development including a run of houses with a terrace that over-looked the river, which was much closer before the Embankment was built. It was this terrace that caused the word "terrace" to take on the meaning of a row of houses. Torn down in 1935 and replaced with the art deco New Adelphi building. It was the demolition of the Adelphi that was, at least partially, responsible for the creation of the Georgian Society in 1937.
The Rise and Fall of the Adelphi is a very useful page with excellent photos.
While thinking of how London has changed the English language, in the field of architecture at least, let's examine "Mews". From the French, it used to mean a place where hawks (kept for hunting) were confined during their moulting seasons. From 1377 the King's Mews was at Charing Cross, about where Trafalgar Square now is. In 1537 Henry VIII had it converted to be the royal stables. And hence Mews became the term for all service streets in London built as stables, converted into garages and then converted into rather chic homes for fashionable Londoners, such as John Steed.
The image on this page shows a plainer front elevation than that on the Garrick page. We have to assume that the Victorians added some decorative features, around the windows and the central attic pediment, for example.