Lundonia

Etymology
From via a medieval Germanic intermediate, probably  or  (as Lundonia is found in Saxo Grammaticus' Gesta Danorum).

Proper noun

 * 1)  London

Declension
Note: The plural is used to designate the city in some parts of Saxo Grammaticus' Gesta Danorum (see Liber IX, line 47 or liber XI, line 86) without any seeming shift in meaning (see liber VIII, line 447 for comparison).