e.g. villa, villae, f. house puella, puellae, f. girl
end in –us most of the time, but can end in –er or –ir.
e.g. amicus, amici, m. friend puer, pueri, m. boy
N.B. the genitive (the second word) always ends in –i.
Can end in anything. You identify them by the –is in the genitive, the second word listed.
e.g. canis, canis, m/f. dog mater, matris, f., mother
1st declension - Via, viae, f., road
2nd declension – Vir, viri, m. man
3rd declension Pater, patris, m. father