Word Unit: obscur- (Latin: dark, dusky; indistinct, uncertain; unintelligible; vague; ambiguous)
Word Unit: obsolesc-, obsolescent-, obsolet- (Latin: to wear out, to grow old; to fall into disuse; to grow out of use; elderly, older)

Related "old; old age, elder" units: gero-; presbyo-; sen-; veter-.

Word Unit: obtusi- + (Latin: to blunt, dull; from ob- "against" plus tundere, "to beat, strike")
Word Unit: occult- (Latin: secret, hidden, concealed)

A cross reference of other word family units that are related directly, or indirectly, to: "secret, hidden, confidential, concealed": ceal-; clandesti-; crypto-; myster-; orgy; stego-, stegano-.

Word Unit: Oceanic Sounds in a Realm of Silence (A noisy silence in the waters of the oceans and the seas)
Word Unit: oceano-, ocean- + (Greek > Latin: "the great river encompassing the whole earth"; hence, the "great Outward Sea" [as opposed to the "Inward" or Mediterranean]; the ocean)

Inter-related cross references, directly or indirectly, involving the "sea" and the "ocean" bodies of water: abysso- (bottomless); Atlantic; batho-, bathy- (depth); bentho- (deep, depth); halio-, halo- (salt or "the sea"); mare, mari- (sea); necto-, nekto- (swimming); pelago- (sea, ocean); plankto- (drifting); thalasso- (sea, ocean).

Cross references of word families that are related directly, or indirectly, to: "river, stream": amni-; fluvio-; meand-; potamo-; ripari-.

Word Unit: ocelli-, ocell- + (Latin: "little eye", a diminutive of oculus, "eye"; spotted, dotted; as if with tiny eyes)

Related references to "eye" or "eye part" word families: blepharo-; core-; corneo-; eye, eyes; irido-; lenti-, lens-; lenticulo-; oculo-; op-, -optic; ophthalmo-; phaco-; pupillo-; retino-; uveo-.

Word Unit: ochlo-, ochl- + (Greek: mob [people])

Related "people, human" word units: anthropo-; demo-; ethno-; popu-; publi-.

Word Unit: ochro-, ochr- (Greek: the color yellow; pale, wan, or sallow)
Word Unit: ochtho-, ochth- (Greek: any elevation, bank, hill, mound)
Word Unit: octa-, octo-, oct-, octi-, octon- (Greek > Latin: eight, eighth)
Word Unit: octothorp (an explanation of what it is and where it came from)
Word Unit: oculo-, ocul- + (Latin: eye[s]; sight)

Related references to "eye" or "eye part" word families: blepharo-; core-; corneo-; eye, eyes; irido-; lenti-, lens-; lenticulo-; ocelli-; op-, -optic; ophthalmo-; phaco-; pupillo-; retino-; uveo-.

Word Unit: ode,-ode, -odal, -odeon, -ody (Greek > Latin: song, lyric poem)
Word Unit: odi-, noi-, noy- (Latin: to hate, hatred, hateful; despise)

Related "hate, hatred" word sources: miso-; stygio-.

Word Unit: odonto-, odont-, odon-, -odont, -odonic, -odontic, -odontia, -odontoid; -dont, -donts, -dontia, -dontic, -dontoid (Greek: tooth, teeth)

Related "tooth, teeth" word units: bruxo-; dento-.

Word Unit: odori-, odor-, odoro- (Latin: smell, odor)

Inter-related cross references, directly or indirectly, involving word units meaning "smell, odor": arom-; brom-; olfacto-; osmo-; osphresio-; ozon-.

Word Unit: odyn-, odyno-, -odynia, -odynic,-odyne, -odyn, -dyne, -dynia + (Greek: οδυνη, pain)

Cross references related to "pain, hurt; suffering, injury" word families: -agra; algesi-; algo-; angina-; dolor-; Masochism; noci-; poen-; pono- (toil, work; pain); Sadism.

Word Unit: oeno-, oen-, eno-, oino-, oin- (Greek: wine, fermented grape juice)
Word Unit: oestr-, oestro-, estr-, estro- + (Greek: a strong desire, orgasm; the sting of a gadfly, anything that drives one mad)