Micro - - wikipedia Micro - Comparison between the micro symbol and the greek letter mu in Linux Libertine This article is about the SI prefix. For other uses, see Micro ( disambiguation ). Look up micro - in Wiktionary, the free dictionary. Micro - ( symbol μ ) is a unit prefix in the metric system denoting a factor of 10 ( one millionth ). Confirmed in 1960, the prefix comes from the Greek μικρός ( mikrós ), meaning `` small ''. The symbol for the prefix comes from the Greek letter μ ( mu ). It is the only SI prefix which uses a character not from the Latin alphabet. `` mc '' is commonly used as a prefix when the character `` μ '' is not available ; for example, `` mcg '' commonly denotes a microgram. Also the letter u instead of μ is allowed by one of the ISO documents. Examples : Typical bacteria are 1 to 10 micrometres in diameter. Eukaryotic cells are typically 10 to 100 micrometres in diameter. SI prefixes Prefix Base 1000 Base 10 Decimal English word Adoption Name Symbol Short scale Long scale yotta Y 1000 10 1000000000000000000000000 septillion quadrillion 1991 zetta Z 1000 10 1000000000000000000000 sextillion trilliard 1991 exa 1000 10 1000000000000000000 quintillion trillion peta 1000 10 1000000000000000 quadrillion billiard tera 1000 10 1000000000000 trillion billion 1960 giga 1000 10 1000000000 billion milliard 1960 mega 1000 10 1000000 million 1873 kilo k 1000 10 1000 thousand 1795 hecto h 1000 10 100 hundred 1795 deca da 1000 10 10 ten 1795 1000 10 one -- deci d 1000 10 0.1 tenth 1795 centi 1000 10 0.01 hundredth 1795 milli m 1000 10 0.001 thousandth 1795 micro μ 1000 10 0.000 001 millionth 1873 nano n 1000 10 0.000 000 001 billionth milliardth 1960 pico p 1000 10 0.000 000 000 001 trillionth billionth 1960 femto f 1000 10 0.000 000 000 000 001 quadrillionth billiardth 1964 atto 1000 10 0.000 000 000 000 000 001 quintillionth trillionth 1964 zepto z 1000 10 0.000 000 000 000 000 000 001 sextillionth trilliardth 1991 yocto y 1000 10 0.000 000 000 000 000 000 000 001 septillionth quadrillionth 1991 Jump up ^ Prefixes adopted before 1960 already existed before SI. 1873 was the introduction of the CGS system. Contents 1 Symbol encoding in character sets 2 Other abbreviating conventions 3 See also 4 References Symbol encoding in character sets The official symbol for the SI prefix micro - is a Greek lowercase mu ( μ ). For reasons stemming from its design, there are two different characters in Unicode, which appear slightly different in some fonts, although most fonts use the same glyph. The micro sign ( μ ) is encoded in the `` Latin - 1 Supplement '' range identical to ISO / IEC 8859 - 1 ( since 1987 ), at U + 00B5 ( Alt + 0181 ), residing at this codepoint also in DEC MCS ( since 1983 ) and ECMA - 94 ( since 1985 ). The Greek letter ( μ ) is encoded in the Greek range at U + 03BC ( Alt + 956 ). According to The Unicode Consortium, the Greek letter character is preferred, but implementations must recognize the micro sign as well. In circumstances, in which only the Latin alphabet is available, ISO 2955 ( 1974, 1983 ), DIN 66030 ( Vornorm 1973 ; 1980, 2002 ) and BS 6430 ( 1983 ) allow the prefix μ to be substituted by the letter u ( or even U, if lowercase letters are not available ), as, for example, in um for μm, or uF for μF. Similar, capacitor values according to the letter and digit code defined in IEC 60062 ( IEC 62 ) ( since 1952 ), EN 60062, DIN 40825 ( 1973 ), BS 1852 ( 1974 ), IS 8186 ( 1976 ) etc. can be written as 4u7 ( or 4U7 ) instead of 4μ7 if the Greek letter μ is not available. Other abbreviating conventions In some health care institutions, house rules deprecate the standard symbol for microgram, `` μg '', in prescribing or chart recording, because of the risk of misdose via the misreading of poor handwriting. The two alternatives are to abbreviate as `` mcg '' or to write out `` microgram '' in full ( see also List of abbreviations used in medical prescriptions ). But this deprecation, focused on bedside misdose avoidance in contexts where handwriting is often present, does not extend to all health - care contexts and institutions ( for example, some clinical laboratories ' reports adhere to it, whereas others do n't ), and in physical sciences academia, `` μg '' remains the sole official abbreviation. In medical data exchange according to the Health Level 7 ( HL7 ) standard, the μ can be replaced by u as well. See also Micrometre Microsecond Square micrometre List of commonly used taxonomic affixes References Jump up ^ International Bureau of Weights and Measures ( 2006 ), The International System of Units ( SI ) ( PDF ) ( 8th ed. ), ISBN 92 - 822 - 2213 - 6, archived ( PDF ) from the original on 2017 - 08 - 14 Jump up ^ ISO 2955, table 2. Jump up ^ Biology by Campbell & Reece tenth edition page 98 Ch. 6 A Tour of the Cell Jump up ^ Prefixes of the International System of Units, International Bureau of Weights and Measures ( page visited on 9 May 2016 ). Jump up ^ ( Unicode 1.0, 1991 ) Jump up ^ Unicode Technical Report # 25 Jump up ^ ISO 2955 - 1974 : lnformation processing - Representations of SI and other units for use in systems with limited character sets ( 1st ed. ). 1974. Jump up ^ `` Table 2 ''. ISO 2955 - 1983 : lnformation processing - Representations of SI and other units for use in systems with limited character sets ( PDF ) ( 2nd ed. ). 1983 - 05 - 15. Retrieved 2016 - 12 - 14. ( 1 ) Jump up ^ Vornorm DIN 66030 ( Preliminary standard DIN 66030 ) ( in German ). January 1973. Jump up ^ DIN 66030 : Darstellungen von Einheitennamen in Systemen mit beschränktem Schriftzeichenvorrat ( in German ) ( 1st ed. ). 1980. Jump up ^ `` Neue Normen für die Informationsverarbeitung ''. Computerwoche ( in German ). 1981 - 01 - 09. Archived from the original on 2016 - 12 - 14. Retrieved 2016 - 12 - 14. Jump up ^ DIN 66030 : 2002 - 05 - Informationstechnik - Darstellung von Einheitennamen in Systemen mit beschränktem Schriftzeichenvorrat ( Information technology - Representation of SI and other units in systems with limited character sets ) ( in German ). Beuth Verlag ( de ). May 2002. Retrieved 2016 - 12 - 14. ^ Jump up to : Burtis, Carl A. ; Ashwood, Edward R. ; Bruns, David E. ( 2012 ), Tietz Textbook of Clinical Chemistry and Molecular Diagnostics ( 5th ed. ). Jump up ^ `` Commonly Used UCUM Codes for Healthcare Units ''. HL7 Deutschland e.V. Retrieved 2015 - 11 - 21. Physics portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Micro-&oldid=804292673 '' Categories : SI prefixes Hidden categories : CS1 German - language sources ( de ) Interlanguage link template link number Articles containing Ancient Greek - language text Talk Contents About Wikipedia Беларуская Български Bosanski Brezhoneg Català Čeština Dansk Español Esperanto Euskara فارسی Français Galego 한국어 Հայերեն हिन्दी Hrvatski Bahasa Indonesia Italiano עברית ქართული Lietuvių മലയാളം Nederlands 日本 語 Norsk Norsk nynorsk ភាសា ខ្មែរ Plattdüütsch Polski Português Ripoarisch Русский Scots Sicilianu Simple English Slovenščina کوردی Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska Türkçe Українська Tiếng Việt 中文 Edit links This page was last edited on 8 October 2017, at 00 : 58. About Wikipedia

Question: in the metric system the prefix micro- denotes
Answer: millionth