Definition of "berlin"

I was then giving some instructions about the forwarding my trunk, and was just going to mount my new purchase in the yard of the inn; when a berlin, apparently belonging to a foreigner of distinction, attended by three French or Swiss servants, drove to the door […] .

1792, Charlotte Smith, Desmond, Broadview, published 2001, page 261

I passed her in his berlin the other day, and just caught a glimpse of very pretty features, with an interesting and sad expression. I believe that she is his wife, because I always believe for the best.

1837, L[etitia] E[lizabeth] L[andon], “Lady Marchmont to Sir Jasper Meredith. Courtiers.”, in Ethel Churchill: Or, The Two Brides. […], volume I, London: Henry Colburn, […], page 263