While the initial l- may be the result of a possible deglutinated definite article (i.e. loterre* became l’oterre), whereby the etymon of the word is Classical Latin lutra, the OED suggests a separate etymology that derives from the Indo-European water n., related to Greek ὕδρα (‘water-snake'), Sanskrit udra (‘aquatic animal’), with cognates in Middle Dutch, Middle Low German, Old Icelandic, Danish etc. (see OED otter n.1). FEW 5,477a, lutra, confirms the relationship with Greek ὕδρα, and explains the initial l- of the Latin etymon through association with lutum (‘mud, dirt’, cf. DMLBS lutum 2 1665c). Romance languages generally keep the l-, and hence the Anglo-Norman synonyms loirre¹ and loutre².