Therefore Sign
?
Therefore sign
Punctuation
apostrophe ''
brackets [ ]( ){ }? ?
colon :
comma ,??
dash -  -  --  -
ellipsis ......???
exclamation mark  !
full stop, period .
guillemets « »
hyphen -
hyphen-minus -
question mark  ?
quotation marks ' '" "' '" "
semicolon ;
slash, stroke, solidus //
Word dividers
interpunct ·
space
General typography
ampersand &
asterisk *
at sign @
backslash \
bullet o
caret ^
dagger + ?
degree °
ditto mark "
inverted exclamation mark ¡
inverted question mark ¿
komejirushi, kome, reference mark ?
number sign, pound, hash, octothorpe #
numero sign No
obelus ÷
multiplication sign ×
ordinal indicator º ª
percent, per mil  % ?
plus and minus + -
equals sign =
basis point ?
pilcrow
prime ???
section sign §
tilde ~
underscore, understrike _
vertical bar, pipe, broken bar |?¦
Intellectual property
service mark ?
Currency
currency sign ¤

Uncommon typography
asterism ?
hedera ?
index, fist ?
interrobang ?
irony punctuation ?
lozenge ?
tie ?
Related
In other scripts

In logical argument and mathematical proof, the therefore sign (?) is generally used before a logical consequence, such as the conclusion of a syllogism. The symbol consists of three dots placed in an upright triangle and is read therefore. It is encoded at ? therefore (HTML `&#8756;` · `&there4;`). For common use in Microsoft Office hold the ALT key and type "8756". While it is not generally used in formal writing, it is used in mathematics and shorthand. It is complementary to ? because (HTML `&#8757;`).

## History

According to Cajori, A History of Mathematical Notations, Johann Rahn used both the therefore and because signs to mean "therefore"; in the German edition of Teutsche Algebra (1659) the therefore sign was prevalent with the modern meaning, but in the 1668 English edition Rahn used the because sign more often to mean "therefore".[1] Other authors in the eighteenth century also used three dots in a triangle shape to signify "therefore," but as with Rahn, there wasn't much in the way of consistency as to how the triangle was oriented; because with its current meaning appears to have originated in the nineteenth century. In this century, the three-dot notation for therefore became very rare in continental Europe, but it remains popular in the British Isles.[2]

## Example of use

Used in a syllogism:

All gods are immortal.
Zeus is a god.
? Zeus is immortal.
x + 1 = 6
? x = 5

## Related signs

A diploma from the Masonic Grande Loge de France showing the symbol as a substitute for the dot of abbreviation.

The inverted form ?, known as the because sign, is sometimes used as a shorthand form of "because". This is Unicode character U+2235.

The therefore sign is sometimes used as a substitute for an asterism ?.

In meteorology, the therefore sign is used to indicate moderate rain on a station model; the asterism indicates moderate snow.

To denote logical implication or entailment, various signs are used in mathematical logic: ->, =>, ?, ?, ?. These symbols are then part of a mathematical formula, and are not considered to be punctuation. In contrast, the therefore sign is traditionally used as a punctuation mark, and does not form part of a logical formula.[3]

The graphically identical sign ? serves as a Japanese map symbol on the maps of the Geographical Survey Institute of Japan, indicating a tea plantation. On other maps the sign, often with thicker dots, is sometimes used to signal the presence of a national monument or ruins.

The character ? in the Tamil script represents the ?ytam, a special sound of the Tamil language.

In Masonic traditions the symbol is used for abbreviation, instead of the usual period. For example "R?W? John Smith" is an abbreviation for "Right Worshipful John Smith" (the term Right Worshipful is an archaic title just as "Land Lord" is and indicates that Brother Smith is a Grand Lodge officer).[4]