Greek & Latin roots of english

amicus, amici

friend(amicable, amiable, amity)

magister, magistri

chief, head(magistrate, magisterial, master, mister)

oculus, oculi

eye(ocular, oculist, binocular)

officium, officii

duty, obligation(office, officer, official, officiate, officious)

periculum, periculi

danger(peril, perilous)

populus, populi

people(populus, popular, population, people)

signum, sigi

sign, seal(sign, signal, signify, significant)