This list includes 20 Big words that start with Y, from “yarmulke” to “yttrium”. They are mostly formal, polysyllabic, and less common words useful for writing, speaking, and study.
Big words that start with Y are established, high-register or rare English words beginning with the letter Y. Notably, “yarmulke” reflects cultural tradition while “yttrium” shows scientific naming from a Swedish locality.
Below you’ll find the table with Word, Etymology, and Definition.
Word: Contains the listed word so you can scan and pick terms for writing or study.
Etymology: Shows origin language and root morphemes so you understand history and nuance of meaning.
Definition: Gives a concise, one-sentence meaning you can use quickly in context or reference.
Big words that start with Y
| Word | Part of speech | Syllable count | Etymology (origin) |
|---|---|---|---|
| yttrium | noun | 3 | Swedish (Ytterby), named from village, 1790s |
| yottabyte | noun | 3 | SI prefix yotta (1991) + byte |
| yottameter | noun | 4 | SI prefix yotta (1991) + metre |
| yottaliter | noun | 4 | SI prefix yotta (1991) + liter |
| yottasecond | noun | 4 | SI prefix yotta (1991) + second |
| yottahertz | noun | 4 | SI prefix yotta (1991) + hertz |
| yottagram | noun | 4 | SI prefix yotta (1991) + gram |
| yoctosecond | noun | 4 | SI prefix yocto (1991) + second |
| yoctometer | noun | 4 | SI prefix yocto (1991) + metre |
| yoctoliter | noun | 4 | SI prefix yocto (1991) + liter |
| yoctogram | noun | 4 | SI prefix yocto (1991) + gram |
| yeomanry | noun | 3 | Middle English yeoman + -ry, c.14th century |
| yeomanhood | noun | 3 | Middle English yeoman + -hood, c.14th century |
| yarmulke | noun | 3 | Yiddish/Hebrew yarmulka, attested 19th–20th c. |
| yeshiva | noun | 3 | Hebrew via Yiddish, medieval origins |
| yesternight | adv. | 3 | Old English/Middle English yester- + night |
| yesteryear | noun | 3 | Middle English yester- + year, c.14th century |
| yohimbine | noun | 3 | From yohimbe (West African tree), botanical name, 19th c. |
| ypsiliform | adj. | 4 | Greek ypsilon + -form, 19–20th century scientific use |
| yiddishkeit | noun | 3 | Yiddish yidish + -keit, early modern Yiddish |
Descriptions
yttrium
A chemical element (atomic number 39); a rare-earth metal named after Ytterby, used in alloys and electronics, technical but commonly listed in dictionaries.
yottabyte
A unit of digital information equal to 10^24 bytes; a technical term used in computing for extremely large data quantities.
yottameter
An SI unit of length equal to 10^24 metres; chiefly used in theoretical or astronomical contexts, rarely in everyday use.
yottaliter
An SI volume unit equal to 10^24 liters; a technical, rarely used measurement term in science/engineering contexts.
yottasecond
A time unit equal to 10^24 seconds; largely theoretical, appears in scientific discussions about extremely long timescales.
yottahertz
A frequency unit equal to 10^24 hertz; technical jargon in physics and engineering for extraordinarily high frequencies.
yottagram
A mass unit equal to 10^24 grams; a technical, rarely used SI-derived term for very large masses.
yoctosecond
A time unit equal to 10^-24 seconds; used in physics and physical chemistry to describe extremely brief intervals.
yoctometer
A length unit equal to 10^-24 metres; highly technical, used only in theoretical or subatomic contexts.
yoctoliter
A volume unit equal to 10^-24 liters; an ultra-small unit appearing in specialized scientific literature.
yoctogram
A mass unit equal to 10^-24 grams; a technical term for describing minuscule masses in science.
yeomanry
A historical/social class of small landowners or a military force of yeomen; somewhat formal or historical in usage.
yeomanhood
The qualities or condition of a yeoman; an archaic/formal term for status or character.
yarmulke
A skullcap worn in Jewish practice; an established loanword used in religious and cultural contexts.
yeshiva
A Jewish religious school or academy for Torah study; a borrowed term now common in religious and academic contexts.
yesternight
An archaic or literary adverb meaning “last night”; chiefly found in poetry, older prose, and stylistic writing.
yesteryear
A nostalgic term for past years or bygone times; common in literary and cultural contexts.
yohimbine
An alkaloid derived from the yohimbe tree, used medicinally; a technical term in pharmacology and herbalism.
ypsiliform
Shaped like the letter Y; a descriptive, chiefly scientific adjective used in morphology and biology.
yiddishkeit
A term describing Jewish culture, spirit, or way of life; a cultural loanword often used in English discussions of identity.