Y
Abbreviation with 4 meanings
| Stands for | Why |
|---|---|
| Meanings | 4 |
| Categories | Texting & Internet Slang, Science & Engineering, Units & Measurements |
| Also written | y |
Y has four meanings. The most common are Why (texting and chat) and Yttrium (chemical element); it can also stand for Yocto- (septillionth) and Yotta- (septillion).
Meanings of Y at a glance
| # | Y stands for | Context |
|---|---|---|
| 1 | Why | Texting & Internet Slang › Texting and Chat |
| 2 | Yttrium | Science & Engineering › Chemical Element |
| 3 | Yocto- (septillionth) | Units & Measurements › Metric and SI Unit |
| 4 | Yotta- (septillion) | Units & Measurements › Metric and SI Unit |
1. Why
Texting & Internet Slang · Texting and Chat Abbreviations
Single-letter homophone for "why," common in texts and comments, often in "y not?" or as a lone "y?" when something seems strange.
Example: Y would you put pineapple on pizza? Explain yourself.
An SMS-era shortcut, alongside U (you) and R (are). Informal and slightly dated, though still used playfully. In other contexts Y can stand for yes, a year or the YMCA, so a question mark helps. Avoid in professional writing.
2. Yttrium
Science & Engineering · Chemical Element Abbreviations
A silvery transition metal with atomic number 39, yttrium is found in YAG (yttrium aluminum garnet) lasers, the red phosphors of old color televisions, white LEDs and yttria-stabilized zirconia ceramics. Yttrium barium copper oxide, discovered in 1987, was the first superconductor to work above the boiling point of liquid nitrogen.
Example: The YBCO tape combines Y, barium and copper oxides and superconducts below about 92 kelvins.
Yttrium, ytterbium, terbium and erbium are all named after Ytterby, a village near Stockholm whose quarry yielded the minerals in which they were found. Finnish chemist Johan Gadolin identified yttria, the oxide, in 1794, and Friedrich Wöhler isolated an impure metal in 1828. Although not a lanthanide, yttrium is counted among the rare earth elements because it occurs with them.
3. Yocto- (septillionth) (y)
Units & Measurements · Metric and SI Unit Abbreviations
Until 2022 the smallest SI prefix, yocto- denotes 10^-24. A proton has a mass of about 1.67 yoctograms, and the yoctosecond appears in theoretical particle physics.
Example: A single proton weighs about 1.67 yg, a number that shows just how small the prefix is.
Adopted in 1991 and derived from Greek okto, eight (1000^-8), with a y added. Before 2022 the prefix range ran from yocto- to yotta-, 48 orders of magnitude; ronto- and quecto- extended the small end. Lowercase y must not be confused with capital Y, yotta-.
4. Yotta- (septillion)
Units & Measurements · Metric and SI Unit Abbreviations
Until 2022 the largest prefix in SI, yotta- denotes 10^24. It appears mostly in astronomy and in projections of global data storage; Earth's mass, for instance, is about 5,970 yottagrams.
Example: Earth's mass works out to roughly 5,970 Yg, a figure few textbooks would ever print that way.
Adopted in 1991 and derived from Greek okto, eight (1000^8), with an initial y added because a bare o could be read as zero. The yottabyte was the largest named data unit until the ronnabyte and quettabyte arrived. Lowercase y, yocto-, sits at the opposite extreme, 10^-24.
Related abbreviations
More texting and chat abbreviations
- WYWH – Wish you were here
- XD – Laughing face (emoticon)
- XO – Hug and kiss
- XOXO – Hugs and kisses
- YKW – You know what
- YMMV – Your mileage may vary
- YOLO – You only live once
- YT – You there?
See all 215 texting and chat abbreviations →