English                                French                                        Latin

husband / wife                         mari / femme                                   maritus / uxor
spouse                                   époux / épouse                                coniunx

son/daughter                            fils / fille                                         filius / filia (baby, filiolus/filiola )

father/mother                            père / mère                                     pater / mater

son-in-law/daughter-in-law         beau-fils / belle-fille                           gener / nuris

brother/sister                           frère / sœur                                      frater / soror
brother-in-law/ sister-in-law        beau-frère / belle-soeur                     levir / ---

grandfather/mother                   grand-père/mère. (aïeul /aïule)          avus /avia                            
grandson/daughter                   petit-fils / petite-fille                          nepos/neptis (baby grandson                                                                                                                                nepotulus)

1st cousin                               cousin germain                                frater patruelis (father's side)
                                              ( c. au premier degré )                      con-sorbrinus (mother's side)                                                                                                                                                    
2nd cousin                              cousin issus de germain                    ---
                                              ( petit cousin )

nephew/niece                          neveu / nièce                                   fratris / sororis

uncle/aunt                               oncle / tante                                    patruus / amita ( father's side)
                                                                                                    avunculus/matertera (mother's side)

 
great uncle/aunt                       grand-oncle/tante                              (father's side)patruus magnus/                                                                                                                           amita magnus
                                                                                                    (mother's side)avunculus magnus/                                                                                                                          matertera magnus                                                                                                                                                           
greatgrandson /daughter           arrière-petit-fils / a. petite fille            pro-nepos /pro-neptis  
greatgrandfather /mother           arrière-grand-père / a.grand-mère      pro-avus / pro-avia
                                                 ( bisaïeul / bisaïeule )

cousin once removed                c. au deuxième degré                        ---                    
" twice "                                      " troisième "  etc.

step father/mother                    beau-père / belle-mère                    vitricus / noverca
step son / daughter                  beau-fils / belle-fille                          privignus / privigna
foster child                              adoptif                                            alumnus

foster father/mother                  père adoptif / mère adoptive.         altor / altrix