Númenorean harbor at the mouth of the river Gwathló, translated “Great Haven” (UT/263), a combination of lond “haven” and daer “great”.
Sindarin
Lond Daer
noun. great haven
lond daer
place name. Great Haven
Elements
Word Gloss lond “(land-locked) haven, (land-locked) haven; [N.] narrow path, strait, pass” daer “great, large”
lond (“entrance to harbour, land-locked haven”), daer (“great”) #Dh could revert to d, assimilated by the preceding d.