Proto-Indo-European Roots

Root/Stem: *n.-
Meaning:  not, un-
Hellenic Greek a-gnótos 'unknown'
Italic Latin i-gnotus 'unknown' < *in-gnótos
Celtic Common Celtic *in-
Old Irish in-gnad 'unknown'
Indic Sanskrit a-jñátas 'unknown'
Iranian Avestan a-jyamna 'unending'
Armenian Armenian an-canawth 'unknown'
Germanic Common Germanic *un- 'not' > 
Gothic un-kunþs 'unknown', Old English un-cnáwen
Notes: We tried to pick up the same word 'unknown' from all possible languages of the family in order to show that the Proto-language can be reconstructed not only by roots, but also on the level of the whole words. The prefix *n.- in Proto-Indo-European marked words with a negative meaning and could be used for both nominal and verbal parts of speech. It was cognate to another particle *ne which again is met very frequently in Indo-European.