The process by which two photons combine in a nonlinear medium to produce a higher-energy photon with a frequency that is the sum of those of the two photons

upconvertverb

To convert (an audio or video signal, etc.) from a lower quality or resolution to a higher one.

upconvertedadj

Modified using upconversion.

upcoreadj

Describing a sample taken from further up a core.

Upcottname

A surname from Old English.

upcountryadj

Living or situated remote from the seacoast.

upcourtadv

Toward a team's offensive basket, the basket at which points are scored

upcranedadj

Craned upward.

upcrawlverb

To crawl upward.

upcreekadv

Towards the source of a creek.

upcreepnoun

A gradual movement upwards.

upcroppingnoun

Something that crops up, or occurs unexpectedly.

upcrossingsnoun

plural of upcrossing

upcryverb

To outcry.

upcurlverb

To curl up.

upcurrentnoun

An upward-moving current.

upcurvenoun

An upward curve.

upcurvedadj

Curving upwards.

upcutverb

To cut (audio or video) too short, so that a small portion is lost or overlaps the adjoining item.

upcycleverb

To convert (waste materials, etc.) into new materials or products of higher quality and greater functionality.

upcycledadj

Of waste materials, etc.: converted into new materials or products of higher quality and greater functionality.

upcyclernoun

One who upcycles.

upcyclingnoun

The act of converting (waste materials, etc.) into new materials or products of higher quality and greater functionality.

updartverb

To dart upward.

updatableadj

That can be updated.

updatenoun

An additional piece of information, an addition to existing information.

update one's priorsverb

To change one's beliefs in the face of new evidence.

updateabilitynoun

The quality of being updateable.

Spelling & Dictionary Insight

The English alphabetical index for the letter U contains 23,789 headwords drawn from our Wiktionary-derived dictionary table. At 50 entries per page the browse splits into 476 pages, and you are currently viewing page 436. 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 "U" 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.