- observed activity
- one who applies colour
- object_oriented
- opened up
- orange rind
- one's credit
- Ornithogalum umbellatum
- Ornithogalum pyrenaicum
- of the lunar race
- one involved in low deeds
- of or belonging to a foreign country
- opisthotones
- oblique fracture
- oblique left atrium vein
- orthotropous
- one_address
- on the big side
- on the large side
- omphalopagus
- one at a time
- one who is dedicated to god
- one who is equipped with a
- one who realises the supreme truth
- one who has capability to relish
- one who has conquered the heaven
- one's due
- orographic
- occupational hygiene
- one's own will
- of that ilk
- on the alert
- one hundred seventy
- on the watch
- one hundred quadrillion
- one of the four major dravidian languages spoken in the extreme south indian state of kerala
- omen
- omental
- opponens pollicis
- opponent
- one who draws a line or demarcates
- one of the two kinds of
- one of the nine rasas — according to indian poetics
- one of the six major indian philosophical systems
- of seven months
- of sixty years of age
- outsmart
- outgeneral
- outflow
- outflowing
- outdraw