O
| obat rekreasi | |
| obat sulpha | |
| octadecanoate.dll | |
| octupole | |
| ohm | |
| oker | |
| oksalat | |
| oksazol | |
| oksida | |
| oksida nitrat | |
| oksidan | |
| oksidasi | |
| oksidasi-reduksi | |
| oksigen | |
| oksigenat | |
| oksikodon | |
| oktaf | |
| oktahidrat | |
| oktan | |
| oktanitrokuban | |
| oktavalen | |
| oktet | |
| oktogen | |
| oleate | |
| olefin | |
| oleum | |
| oligonukleotida | |
| oligopeptida | |
| oligosakarida | |
| olivin | |
| opal | |
| operator | |
| operator gradien | |
| opioid | |
| optik elektron | |
| optik geometris | |
| orbit | |
| orbit geostasioner | |
| orbit geosynchronous | |
| orbital | |
| orbital atom | |
| orbital molekul | |
| orbital molekul kosong paling rendah | |
| orbital pi | |
| orbital subjacent | |
| orbital-d | |
| ORD | |
| oregonator | |
| organisasi mandiri | |
| organo- | |
| ornithine | |
| orpiment | |
| orthoplumbate | |
| orto- | |
| ortohelium | |
| ortohidrogen | |
| ortoklas | |
| ortorombik | |
| ortosilikat | |
| ortostannat | |
| osilator anharmonic | |
| osilator harmonik | |
| osilator kristal | |
| osiloskop sinar katoda | |
| osmiridium | |
| osmium | |
| osmium (IV) oksida | |
| osmometer | |
| osmosa | |
| Ostwald, Friedrich Wilhelm (1853–1932) | |
| oximes | |
| oxo- | |
| oxyhaemoglobin | |
| ozon | |
| ozonida | |
| ozonisasi | |
| ozonolisis |