English Words: O
15,494 words · Page 171 of 310
An aerial photograph that has been geometrically corrected (orthorectified) such that the scale of the photograph is uniform, meaning that the photo can be considered equivalent to a map.
The geometrical correction of aerial photographs so that their displayed distances are rendered uniform and can be measured like a map.
Either of the two planes in the monoclinic system which are parallel to the vertical and orthodiagonal axes.
An orthorhombic-dipyramidal black mineral containing boron, iron, magnesium, manganese, and oxygen.
Of or relating to orthopnea—a morbid condition in which respiration can be performed only in an erect posture.
Shortness of breath when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair.
The state of a positronium exotic atom in which the positron and electron have parallel spins
Any of the genus Orthopoxvirus of poxviruses, including smallpox and many species isolated from mammals.
Correct in practice (though not necessarily in opinion or belief); practically right, doing the right actions.
Correctness of practice or action in regard to religion and especially religious ritual, particularly in juxtaposition to "correct doctrine", or "correct belief" (that is, "orthodoxy").
branch of psychiatry concerned with the prevention of mental illness, especially in the young
An approach to psychology focusing on positive human traits such as love, creativity, and personal autonomy.
Any of the insects historically included in the order Orthoptera, including the cockroaches, earwigs, praying mantises, etc.
A very pure quartz sandstone composed of usually well rounded quartz grains cemented by silica.
Relative to a grid of circles surrounding a point and lines starting at that point; such a graph has alternate circular and radial components
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 171. 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.