very, extremely · in particular, particularly · synonym of eritellen (“specifying, allocating”)
eş: epätavallisen, erinomaisen, hirveän, huikean, hyvin, huomattavan
köken: eri + -ttäin (distributive plural). Equivalently, from the second infinitive instructive of erittää (“to specify”) (standard erittäen), and erittäin is very likely one of the prototypes for the -ttain suffix in general. Semantic evolution seems to run from senses 3-to-2-to-1.
köken: Etymology tree Proto-Indo-European *per- Proto-Italic *per Latin per Proto-Indo-European *kʷ- Proto-Indo-European *kʷís Proto-Italic *kʷis Proto-Indo-European *kʷ- Proto-Indo-European *kʷos Proto-Italic *kʷoi Latin quam Latin perquam From per + quam.
köken: From Old Galician-Portuguese avondo (13th century, Cantigas de Santa Maria), from Latin abundus, an adjective likely based on Latin abundē (“abundantly”).
köken: Etymology tree Esperanto tre Russian -яга (-jaga)der. Proto-Indo-European *méǵh₂s Proto-Hellenic *mégas Ancient Greek μέγᾰς (mégăs)der. Esperanto -eg- Esperanto -e Esperanto treege From tre + -eg- + -e.