English Words: O
15,494 words · Page 137 of 310
The branch of physics that deals with the interaction of light with electronic devices, or the production of light from such devices
The science of optical devices incorporating fluids, especially such microfluidic devices
A science that combines optics and genetics, aiming at controlling cellular processes with light. The cells are made responsive to light using genetics and then activated using specific wavelengths.
An image of external objects fixed on the retina by the photochemical action of light on rhodopsi.
The production of an optogram on the retina by the photochemical action of light on the visual purple; the fixation of an image in the eye.
Spelling & Dictionary Insight
The English alphabetical index for the letter O contains 15,494 headwords drawn from our Wiktionary-derived dictionary table. At 50 entries per page the browse splits into 310 pages, and you are currently viewing page 137. Every row above is a dictionary-backed entry with a canonical slug, and each links through to a full definition page with pronunciation, senses, etymology, and related-word data where available.
On this page 50 of 50 entries carry a part-of-speech tag and 50 carry at least one stored definition. Coverage varies across letters because Wiktionary volunteers build entries at different speeds for different parts of the alphabet, letters with common starting sounds (S, C, T, P) usually have the densest coverage, while less frequent starters (X, Q, Z) tend to have shorter but more specialised lists. PlainSpell surfaces whatever data is present and links back to the source when a definition is not yet recorded.
For readers using this index as a spelling reference, the guarantee is that every form you see on the list is a documented English headword, not a guess, not a derived inflection lacking a lemma row. If a word you expected to find is absent from the "O" list, it usually means the form exists only as an inflection of another lemma (e.g. a past participle stored under the infinitive) or the entry has not yet been imported from Wiktionary. Use the search bar or the misspelling lookup to resolve these cases.