ob	on account of, for, according to
obdormitus est	he fell asleep, died
obierunt	they died, have died
obiit	he/she died, went away, departed
[obiit sine prole]	[died without issue]
obitus	death, died
obstetrix (obstetricis)	midwife
octavus	eighth
octavus decimus	eighteenth
octingentesimus	eight hundredth
octingenti	eight hundred
octo	eight
octobris	of October
octogenarius	a person in his eighties
octogesimus	eightieth
octoginta	eighty
officialis	official
olim	formerly, once (sometimes denotes a deceased person)
omnis	all, every
operarius	day laborer
oppidum	city, town
orbus	orphan
origo (originis)	origin, birth
oriundus, ex	originating (from), born
orphanus	orphan
ortus	origin, birth
ovilius	shepherd