In Latin, 'amicus' belongs to the second declension. Most second-declension nouns end in '-i' in the genitive singular and '-um' in the accusative singular.
(grammar): The act of declining a word; the act of listing the inflections of a noun, pronoun or adjective in order.
Origin of declension
Middle English declensonfrom Old French declinaisonfrom Latin dēclīnātiōdēclīnātiōn-grammatical declension, declinationdeclination
Aryan declension naturally disappeared with the loss of final syllables.
At once he welcomed the new "power" with an unquestioning evidence which could be shaken by neither the remonstrances or desertion of his dearest friends, the recantation of some of the principal agents of the "gifts," his own declension into a comparatively subordinate position, the meagre and barren results of the manifestations, nor their general rejection both by the church and the world.
There had indeed been previous immigrations, but the passage from the desert into the midst of Palestinian culture led to the adoption of the old semi-heathenism of the land, a declension, and a descent from the relative simplicity of tribal life.
The differences in declension between Old Persian and ad are unimportant.
Jnfiexion.There is no trace of declension either in Castilian or in Portuguese.