My Grammar and I (Or Should That Be 'Me'?): Old-School Ways to Sharpen Your English

hippopotamus hippopotamuses, hippopotami
octopus
octopi, octopodes, octopuses
oxymoron
oxymorons, oxymora
necropolis
necropolises, necropoles, necropoleis,
necropoli
rhinoceros
rhinoceroses, rhinoceros, rhinoceri,
rhinocerotes
syllabus
syllabuses, syllabi
terminus
termini, terminuses
uterus
uteri, uteruses
Swot’s Corner: Octopus is a one-word minefield, because it is a Latinized form
of a Greek word, oktopous , whose ‘correct’ plural form would be octopodes .
Chambers Dictionary describes that as archaic and gives octopuses as the correct
form. ‘Octopi ,’ it says austerely, ‘is wrong.’ But right or wrong, if enough
people use it, octopi , which has no justification in etymological terms, will work
its way into the dictionaries in time.
Keeping up with the Joneses
When  we  talk  about  a  family  in  the  plural,  we  need  to  add  an  s  to  the  family
name , e.g. the Smiths , the Windsors . However, if the family name ends in s , x
, ch , sh , or z , we add -e s: the Joneses , the Foxes , the Bushes etc. Same rules as
churches and waltzes , see
here
.