Rules for forming plurals of Greed & Latin words
1. Words ending in "a" add "e" to form the plural:
urethra urethrae
ulna ulnae
fibula gibulae
2. Words ending in "is change to "es" to form the plural:
brevis breves
cirrhosis cirrhoses
diagnosis dinoses
naris nares
3. Words ending in "ix", "yx" or "ex" change to "ices" for plurals:
appendix appendices
index indices
calyx calyces
varix varices
4. Words ending in "oma" add "ta" to form the plurals:
adenoma adenomata
carcinoma carcinomata
stoma stomata
5. Words ending in "os" and "us" change to "i" to form the plural:
oculus oculi
bacillus bacilli
bronchus bronchi
gyros gyri
6. Words ending in "um" or on" drop these endings and add "a" to form the plural:
septum septa
datum data
ganglion ganglia
diverticulum diverticula
7. Words ending in "d" add "es" to form the plural:
glans glandes
gonad gonades
anthracoid anthracoides
The modern form, adding an "s" to the singular, is also very often preferable.
glans = "gland"
8. Words ending in "er" add "a" to form the plural:
cadaver cadaver
Modern form: cadavers
9. Certain words ending in "itis" for their plurals by changing to "idites":
arthritis arthridites
myocarditis myocardidites
neuritis neuritidites
The following are a few modern therms that are exceptions to the rules.
To explain the reasons behind each would require consideration of the
inflections, declensions, neuters, etc. of Latin & Greek languages.
foramen foramina
femur femora
albicans albicantia
dens dentes
epididymis epididymides
os (mouth) ora
os (bone) ossa
pes pedes
viscus viscera
