Noun
i-stem (plural i-stems)
(linguistics) A word, especially a noun in Indo-European linguistics, whose stem ends in /i/.
By the parisyllabic rule, canis should be a masculine i-stem and thus differ from the non-i-stems by having an extra –i– in the plural genitive form: *canium. Source: Internet
The rules for determining i-stems from non-i-stems and "mixed" i-stems should be thought of more as "guidelines" than "rules": even among the Romans themselves, the categorization of a 3rd declension word as an i-stem or non-i-stem was quite fluid. Source: Internet
Note the alternative i-stem endings indicated in parentheses. Source: Internet
Often these are the same nouns that had an -e in the nominative/accusative singular of Old English (they, in turn, were inherited from Proto-Germanic ja-stem and i-stem nouns.) The distinct dative case was lost in early Middle English. Source: Internet
The nominative of the strong masculine declension and some i-stem feminine nouns uses one such -r (ʀ). Source: Internet