Similar to ovis
- opisthotonos – A disease where the body is curved backward
- opusculus – a little or small work, a small book
- oraculum – a solemn statement, oracle, prophecy, words of a god
- odium – abhorrence, hatred
- orexis – appetite, desire
- oriundus – arising from, born, coming from, springing from
- olim – at a future time, at that time, for a long time now, formerly, once