U.S. Government Printing Office Style Manual/Signs and Symbols

by United States Government Printing Office

10. Signs and Symbols

10.1.

The increased use of signs and symbols and their importance in technical and scientific work have emphasized the necessity of standardization on a national basis and of the consistent use of the standard forms.

10.2.

Certain symbols are standardized—number symbols (the digits, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9); letter symbols (the letters of the alphabet, a, b, c, d, etc.); and graphic symbols (the mathematical signs +, -, ±, x, ÷).

10.3.

The signs +, -, ±, x, and ÷, etc., are closed against accompanying figures and symbols. When the x is used to indicate "crossed with" (in plant or animal breeding) or magnification, it will be separated from the accompanying words by a space.

i-vii + 1-288 pages

Early June × Bright (crossed with)

× 4 (magnification)

The equation A+B

The result is 4x4

miles ÷ gallons

20,000±5,000

Symbols with figures

10.4.

In technical publications the degree mark is used in lieu of the word degree following a figure denoting measurement.

10.5.

Following a figure, the spelled form is preferred. The percent symbol is used in areas where space will not allow the word percent to be used.

In that period the price rose 12, 15, and 19 percent.

not In that period the price rose 12 percent, 15 percent, and 19 percent.

10.6.

Any symbol set close up to figures, such as the degree mark, number mark, dollar mark, or cent mark, is used before or after each figure in a group or series.

$5 to $8 price range

5'-7' long, not 5-7' long

3₵ to 5₵ (no spaces)

±2 to ±7; 2°±1°

1. 61 to #64

but

§ 12 (thin space)

❡1951 (thin space)

from 15 to 25 percent

45 to 65 °F not 45° to 65° F

Letter symbols

10.7.

Letter symbols are set in italic (see rule 10.8) or in roman (see rule 9.56) without periods and are capitalized only if so shown in copy, since the capitalized form may have an entirely different meaning.

Equations

10.8.

In mathematical equations, use italic for all letter symbols—capitals, lowercase, small capitals, and superiors and inferiors (exponents and subscripts); use roman for figures, including superiors and inferiors.

10.9.

If an equation or a mathematical expression needs to be divided, break before +, -, =, etc. However, the equal sign is to clear on the left of other beginning mathematical signs.

10.10.

A short equation in text should not be broken at the end of a line. Space out the line so that the equation will begin on the next line; or better, center the equation on a line by itself.

10.11.

An equation too long for one line is set flush left, the second half of the equation is set flush right, and the two parts are balanced as nearly as possible.

10.12.

Two or more equations in a series are aligned on the equal signs and centered on the longest equation in the group.

10.13.

Connecting words of explanation, such as hence, therefore, and similarly, are set flush left either on the same line with the equation or on a separate line.

10.14.

Parentheses, braces, brackets, integral signs, and summation signs should be of the same height as the mathematical expressions they include.

10.15.

Inferiors precede superiors if they appear together; but if either inferior or superior is too long, the two are aligned on the left.

Chemical symbols

10.16.

The names and symbols listed below are approved by the International Union of Pure and Applied Chemistry. They are set in roman without periods.

Element	Symbol	Atomic No.	Element	Symbol	Atomic No.
Actinium	Ac	89	Mendelevium	Md	101
Aluminum	Al	13	Mercury	Hg	80
Americium	Am	95	Molybdenum	Mo	42
Antimony	Sb	51	Neodymium	Nd	60
Argon	Ar	18	Neon	Ne	10
Arsenic	As	33	Neptunium	Np	93
Astatine	At	85	Nickel	Ni	28
Barium	Ba	56	Niobium	Nb	41
Berkelium	Bk	97	Nitrogen	N	7
Beryllium	Be	4	Nobelium	No	102
Bismuth	Bi	83	Osmium	Os	76
Bohrium	Bh	107	Oxygen	O	8
Boron	B	5	Palladium	Pd	46
Bromine	Br	35	Phosphorus	P	15
Cadmium	Cd	48	Platinum	Pt	78
Calcium	Ca	20	Plutonium	Pu	94
Californium	Cf	98	Polonium	Po	84
Carbon	C	6	Potassium	K	19
Cerium	Ce	58	Praseodymium	Pr	59
Cesium	Cs	55	Promethium	Pm	61
Chlorine	Cl	17	Protactinium	Pa	91
Chromium	Cr	24	Radium	Ra	88
Cobalt	Co	27	Radon	Rn	86
Copper	Cu	29	Rhenium	Re	75
Curium	Cm	96	Rhodium	Rh	45
Darmstadtium	Ds	110	Roentgenium	Rg	111
Dubnium	Db	105	Rubidium	Rb	37
Dysprosium	Dy	66	Ruthenium	Ru	44
Einsteinium	Es	99	Rutherfordium	Rf	104
Erbium	Er	68	Samarium	Sm	62
Europium	Eu	63	Scandium	Sc	21
Fermium	Fm	100	Seaborgium	Sg	106
Fluorine	Fl	9	Selenium	Se	34
Francium	Fr	87	Silicon	Si	14
Gadolinium	Gd	64	Silver	Ag	47
Gallium	Ga	31	Sodium	Na	11
Germanium	Ge	32	Strontium	Sr	38
Gold	Au	79	Sulfur	S	16
Hafnium	Hf	72	Tantalum	Ta	73
Hassium	Hs	108	Technetium	Tc	43
Helium	He	2	Tellurium	Te	52
Holmium	Ho	67	Terbium	Tb	65
Hydrogen	H	1	Thallium	Tl	81
Indium	In	49	Thorium	Th	90
Iodine	I	53	Thulium	Tm	69
Iridium	Ir	77	Tin	Sn	50
Iron	Fe	26	Titanium	Ti	22
Krypton	Kr	36	Tungsten	W	74
Lanthanum	La	57	Uranium	U	92
Lawrencium	Lr	103	Vanadium	V	23
Lead	Pb	82	Xenon	Xe	54
Lithium	Li	3	Ytterbium	Yb	70
Lutetium	Lu	71	Yttrium	Y	39
Magnesium	Mg	12	Zinc	Zn	30
Manganese	Mn	25	Zirconium	Zr	40
Meitnerium	Mt	109

Standardized symbols

10.17.

Symbols duly standardized by any national scientific, professional, or technical group are accepted as preferred forms within the field of the group. The issuing office desiring or requiring the use of such standardized symbols should see that copy is prepared accordingly.

Signs and symbols

10.18.

The following list contains some signs and symbols frequently used in printing. The forms and style of many symbols vary with the method of reproduction employed. It is important that editors and writers clearly identify signs and symbols when they appear within a manuscript.

ACCENTS

ˊ   acute

˘   breve

¸   cedilla

ˆ   circumflex

¨   dieresis

ˋ   grave

ˉ   macron

˜   tilde

ARROWS

→ direction

↖ direction

⮣ direction

⤴̣ direction

⤵̣ direction

⬅ bold arrow

⇨ open arrow

⇄ reversible reaction

BULLETS

● solid circle; bullet

• bold center dot

• movable accent

CHEMICAL

‰ salinity

♏︎ minim

⇵ exchange

↑ gas

CIRCLED SYMBOLS

◷ angle in circle

⦷ circle with parallel rule

⎊ triangle in circle

⊙ dot in circle

◬⃝ dot in triangle in circle

⊕ cross in circle

© copyright

① Ceres

② Pallas

③ Juno

④ Vesta

CODE

• No. 1 6 pt. code dot

• No. 2 8 pt. code dot

• No. 3 10 pt. code dot

● No. 4 8 pt. code dot

● No. 4 10 pt. code dot

— No. 1 6 pt. code dash

— No. 2 8 pt. code dash

— No. 3 10 pt. code dash

➖ No. 4 8 pt. code dash

➖ No. 4 10 pt. code dash

COMPASS

° degree

°̣ degree with period

′ minute

′̣ minute with period

″ second

″̣ second with period

″̲ canceled second

DECORATIVE

✚ bold cross

✠ cross patte

cross patte

cross patte

🏶 (184 N)

🗝 key

❦ (206 N)

¶ paragraph

ELECTRICAL

𝓡 reluctance

↔ reaction goes both right and left

↕ reaction goes both up and down

↕ reversible

→ direction of flow; yields

→ direct current

⇆ electrical current

⇆ reversible reaction

⇄ reversible reaction

⇆ alternating current

⇄ alternating current

⇌ reversible reaction beginning at left

⇋ reversible reaction beginning at right

Ω ohm; omega

MΩ megohm; omega

μΩ microohm; mu omega

ω angular frequency, solid angle; omega

Φ magnetic flux; phi

Ψ, dielectric flux; electrostatic flux; psi

γ conductivity; gamma

ρ resistivity; rho

Λ equivalent conductivity

HP horsepower

MATHEMATICAL

 ̅ vinculum (above letters)

∺ geometrical proportion

∹ difference, excess

∥ parallel

∥s parallels

∦ not parallels

| | absolute value

∙ multiplied by

∶ is to; ratio

÷ divided by

∴ therefore; hence

∵ because

∷ proportion; as

≪ is dominated by

> greater than

⫍ greater than

≥ greater than or equal to

≧ greater than or equal to

≷ greater than or less than

≯ is not greater than

< less than

⫎ less than

≶ less than or greater than

≮ is not less than

⪪ smaller than

≤ less than or equal to

≦ less than or equal to

≧ or ≥ greater than or equal to

⋜ equal to or less than

⪙ equal to or less than

⪚ is not greater than equal to or less than

⋝ equal to or greater than

⪚ is not less than equal to or greater than

⫨ equilateral

⊥ perpendicular to

⊢ assertion sign

≐ approaches

≐ approaches a limit

≚ equal angles

≠ not equal to

≡ identical with

≢ not identical with

score

≈ or ≒ nearly equal to

= equal to

~ difference

≃ perspective to

≅ congruent to approximately equal

≏ difference between

≎ geometrically equivalent to

( included in

) excluded from

⊂ is contained in

∪ logical sum or union

∩ logical product or intersection

√ radical

√ root

${\sqrt[{2}]{}}$ square root

${\sqrt[{3}]{}}$ cube root

${\sqrt[{4}]{}}$ fourth root

${\sqrt[{5}]{}}$ fifth root

${\sqrt[{6}]{}}$ sixth root

π pi

ϵ base (2.718) of natural system of logarithms; epsilon

∈ is a member of; dielectric constant; mean error; epsilon

+ plus

➕ bold plus

− minus

➖ bold minus

/ shill(ing); slash; virgule

± plus or minus

∓ minus or plus

× multiplied by

= bold equal

# number

⅌ per

% percent

∫ integral

| single bond

\ single bond

/ single bond

|| double bond

\\ double bond

// double bond

⌬ benzene ring

∂ or δ differential; variation

∂ Italian differential

→ approaches limit of

∿ cycle sine

∫ horizontal integral

∮ contour integral

∝ variation; varies as

∏ product

∑ summation of; sum; sigma

! or ∟ factorial product

MEASURE

℔ pound

ʒ dram

ƒʒ fluid dram

℥ ounce

ƒ℥ fluid ounce

O pint

MISCELLANEOUS

§ section

† dagger

‡ double dagger

℀ account of

℅ care of

score

¶ paragraph

þ Anglo-Saxon

℄ center line

☌ conjunction

⊥ perpendicular to

" or “ ditto

∝ variation

℞ recipe

⊏ move right

⊐ move left

○ or ⊙ or ① annual

⊙⊙ or ② biennial

∈ element of

℈ scruple

ƒ function

! exclamation mark

⊞ plus in square

♃ perennial

⌀ diameter
c̄ mean value of c
∪ mathmodifier
⊂ mathmodifier
⊡ dot in square
◬ dot in triangle
⊠ station mark
@ at

MONEY

¢ cent
¥ yen
£ pound sterling
₥ mills

MUSIC

♮ natural
♭ flat
♯ sharp

PLANETS

☿ Mercury
♀ Venus
🜨 Earth
♂ Mars
♃ Jupiter
♄ Saturn
⛢ Uranus
♆ Neptune
♇ Pluto
☊ dragon's head, ascending node
☋ dragon's tail, descending node
☌ conjunction
☍ opposition
☉ or 🌞︎ Sun
☉̲ Sun's lower limb
☉̅ Sun's upper limb
⦶ solar corona
🜨 solar halo
◍ Moon
🌑︎ new Moon
☽ first quarter
🌓︎ first quarter
🌘︎ third quarter
🌗︎ last quarter
☾ last quarter
🌗︎ last quarter
🌕︎ full Moon
🌝︎ full Moon
☉̶ eclipse of Moon
lunar halo
lunar corona
⚳ Ceres
⚵ Juno

PUNCTUATION

{ } braces
[ ] brackets
( ) parentheses
⟨ ⟩ square parentheses; angle brackets
¡ Spanish open quote
¿ Spanish open quote

SEX

♂ or ♁ male
□ male, in charts
♀ female
○ female, in charts
⚥ hermaphrodite

SHAPES

◆ solid diamond
◇ open diamond
○ circle
▲ solid triangle
△ triangle
□ square
■ solid square
▱ parallelogram
▭ rectangle
⧉ double rectangle
★ solid star
☆ open star
∟ right angle
∠ angle
√ check
✓ check
ß German ss
ß italic German ss
☛ solid index
☚ solid index
☞ index
☜ index

GEOLOGIC SYSTEMS^[1]

Q Quaternary
T Tertiary
K Cretaceous
J Jurassic
🝈 Triassic
P Permian
ℙ Pennsylvanian
M Mississippian
D Devonian
S Silurian
O Ordovician
Ꞓ Cambrian
pꞒ Precambrian
C Carboniferous

VERTICAL

⁠ 5 unit vertical
⁠ 8 point vertical
⁠ 9 unit vertical

WEATHER

⊤ thunder
☈ thunderstorm; sheet lightning
☇ sheet lightning
↓ precipitate
◍ rain
← floating ice crystals
↔ ice needles
▲ hail
🝴 sleet
glazed frost
⏘ hoarfrost
⌵ frostwork
∗ snow or sextile
⊠ snow on ground
drifting snow (low)
fog
haze
Aurora

ZODIAC

♈︎ Aries; Ram
♉︎ Taurus; Bull
♊︎ Gemini; Twins
♋︎ Cancer; Crab
♌︎ Lion
♍︎ Virgo; Virgin
♎︎ Libra: Balance
♏︎ Scorpio; Scorpion
♐︎ Sagittarius; Archer
♑︎ Capricornus; Goat
♒︎ Aquarius; Water bearer
♓︎ Pisces; Fishes

1. Standard letter symbols used by the Geological Survey on geologic maps. Capital letter indicates the system and one or more lowercased letters designate the formation and member where used.