Copy ∩, the intersection symbol, to paste into your math, or type it with Alt+239; the union sign ∪ follows.
Intersection Symbol
∩IntersectionU+2229Ready to copy
36 intersection and union signs. Tap any value to copy it.
36 intersection and union signs. A character and its name both copy the character. A code copies the code.
Character
Name
Code point
Alt code
HTML
LaTeX
U+2229. The sign for what two sets share: A ∩ B holds the elements that lie in both. Alt+239, ∩ in HTML, \cap in LaTeX. Unicode also lists the names cap and hat.
U+222A. A ∪ B holds everything in A or B, or both. Neither Alt code table has it; ∪ in HTML, \cup in LaTeX. Unicode also lists the name cup.
U+22C2. The big intersection, set before a whole family of sets. ⋂ in HTML, \bigcap in LaTeX.
U+22C3. The big union. Placed before other symbols and not between them, the sign is usually drawn at this larger size. ⋃ in HTML, \bigcup in LaTeX.
Made of A, U+2229 and B, the way the formula is written out between two set names.
Made of A, U+222A and B: the elements found in A, in B or in the two together.
U+228E. A cup with a plus in it. Unicode names it multiset union, and some authors write a disjoint union with it. ⊎ in HTML, \uplus in LaTeX.
U+2294. Square cup, a union drawn with corners. A ⊔ B is the usual way to write a disjoint union. ⊔ in HTML, \sqcup in LaTeX.
U+22D2. Two arches, one inside the other. \Cap in LaTeX needs amssymb; ⋒ in HTML.
U+2A40. An arch with a dot under it. ⩀ in HTML.
U+2A43. An arch under a bar. ⩃ in HTML.
U+2A44. An arch with a wedge, the logical and, inside it. ⩄ in HTML.
U+2A4B. Two arches side by side, joined at the foot. ⩋ in HTML.
U+2A4D. An arch closed along the bottom, with serifs at its feet. ⩍ in HTML.
U+2ADB. A fork on a stem; transversal intersection is its name in Unicode. ⫛ in HTML.
U+23E7. Not a set sign. Unicode names it electrical intersection and files it with technical symbols; it joined in version 5.0 (2006).
U+22D3. Two bowls, one inside the other. \Cup in LaTeX needs amssymb; ⋓ in HTML.
U+2A03. The large bowl with a dot in it. It has no HTML name. In LaTeX the unicode-math package names it \bigcupdot.
U+2A04. The large bowl with a plus in it: the big form of ⊎. ⨄ in HTML, \biguplus in LaTeX.
U+2A41. A bowl with a minus in it. Unicode also lists the name z notation bag subtraction.
U+2A42. A bowl under a bar. ⩂ in HTML.
U+2A45. A bowl with a vee, the logical or, inside it. ⩅ in HTML.
U+2A4A. Two bowls side by side, joined at the rim. ⩊ in HTML.
U+2A4C. A bowl closed along the top, with serifs. ⩌ in HTML.
U+2A50. The closed bowl with a small cross in it, which Unicode calls a smash product. ⩐ in HTML.
U+2A46. A union stacked on an intersection. ⩆ in HTML.
U+2A47. An intersection stacked on a union. ⩇ in HTML.
U+2A48. Union over intersection with a bar between them. ⩈ in HTML.
U+2A49. The same pair the other way up: ∩ on top, ∪ below the line. ⩉ in HTML.
U+2293. Square cap, the intersection sign drawn with corners. ⊓ in HTML, \sqcap in LaTeX.
U+2A05. The large square cap, written before a family. In Unicode since version 3.2 (2002).
U+2A06. The large square cup, written before a family. ⨆ in HTML, \bigsqcup in LaTeX.
U+2A4E. Two square caps, one inside the other.
U+2A4F. Two square cups nested the same way.
U+0055. A plain capital letter from the keyboard. The union sign is a character of its own, U+222A, and a search for one does not find the other.
U+006E. A plain small letter. Its arch looks like ∩, but the set sign is U+2229.
The intersection symbol is ∩, U+2229 in Unicode: the sign for what two sets share. Its Alt code is 239. Its partner ∪, the union sign, has no Alt code and is one to copy.
Read the full guide
Union and intersection in math
A ∩ B is the set of elements that lie in both A and B; A ∪ B holds the elements in A, in B or in both. With A = {1, 3, 5, 7} and B = {1, 2, 4, 6, 7}, the union is {1, 2, 3, 4, 5, 6, 7} and the intersection is {1, 7}. Set theory is a topic of discrete math, and statistics uses the same signs: P(A ∩ B) is the probability that A and B both happen.
Typing the two signs
Alt+239 types ∩. A web page writes the pair ∩ and ∪, and LaTeX \cap and \cup, with \bigcap and \bigcup for the big forms.
A U on its side, ⊂, is the subset sign and not a sideways union.
In geometry, two parallel lines in one plane are disjoint: their intersection is empty.
Both signs date from the late 1880s.
Questions and answers
What is the symbol for intersection?
∩, an arch open at the bottom. Between two sets it names the elements they share, so A ∩ B is everything that is in A and also in B. Unicode lists cap as another name for the sign.
When do you use the union symbol in math?
When you want everything that is in either set. A ∪ B holds the elements in A or B, or both. For a disjoint union, where each element keeps a label for the set it came from, the usual sign is ⊔.
What is the upside down union symbol in math?
The intersection sign, ∩. The union sign ∪ opens upward like a cup; the upside down one is U+2229 and keeps only what the two sets share. Unicode lists the names cup and cap for the pair.
What is the Alt code for the intersection and union symbols?
Alt+239 types ∩, and that code is its only keyboard shortcut: the U.S. layout has no Option key for it. Neither Alt code table holds ∪. Neither sign is in ASCII, so plain ASCII text writes the words out.
All 36 intersection and union signs
Start here 8
A∩BA intersection BMade of A, U+2229 and B, the way the formula is written out between two set names.
A∪BA union BMade of A, U+222A and B: the elements found in A, in B or in the two together.
∩IntersectionU+2229. The sign for what two sets share: A ∩ B holds the elements that lie in both. Alt+239, ∩ in HTML, \cap in LaTeX. Unicode also lists the names cap and hat.
⊎Multiset unionU+228E. A cup with a plus in it. Unicode names it multiset union, and some authors write a disjoint union with it. ⊎ in HTML, \uplus in LaTeX.
⋂N-ary intersectionU+22C2. The big intersection, set before a whole family of sets. ⋂ in HTML, \bigcap in LaTeX.
⋃N-ary unionU+22C3. The big union. Placed before other symbols and not between them, the sign is usually drawn at this larger size. ⋃ in HTML, \bigcup in LaTeX.
⊔Square cupU+2294. Square cup, a union drawn with corners. A ⊔ B is the usual way to write a disjoint union. ⊔ in HTML, \sqcup in LaTeX.
∪UnionU+222A. A ∪ B holds everything in A or B, or both. Neither Alt code table has it; ∪ in HTML, \cup in LaTeX. Unicode also lists the name cup.
Show all 36 intersection and union signs (28 more)
Intersection 8
⩍Closed intersection with serifsU+2A4D. An arch closed along the bottom, with serifs at its feet. ⩍ in HTML.
⋒Double intersectionU+22D2. Two arches, one inside the other. \Cap in LaTeX needs amssymb; ⋒ in HTML.
⏧Electrical intersectionU+23E7. Not a set sign. Unicode names it electrical intersection and files it with technical symbols; it joined in version 5.0 (2006).
⩋Intersection beside and joined with intersectionU+2A4B. Two arches side by side, joined at the foot. ⩋ in HTML.
⩀Intersection with dotU+2A40. An arch with a dot under it. ⩀ in HTML.
⩄Intersection with logical andU+2A44. An arch with a wedge, the logical and, inside it. ⩄ in HTML.
⩃Intersection with overbarU+2A43. An arch under a bar. ⩃ in HTML.
⫛Transversal intersectionU+2ADB. A fork on a stem; transversal intersection is its name in Unicode. ⫛ in HTML.
Union 9
⩌Closed union with serifsU+2A4C. A bowl closed along the top, with serifs. ⩌ in HTML.
⩐Closed union with serifs and smash productU+2A50. The closed bowl with a small cross in it, which Unicode calls a smash product. ⩐ in HTML.
⋓Double unionU+22D3. Two bowls, one inside the other. \Cup in LaTeX needs amssymb; ⋓ in HTML.
⨃N-ary union operator with dotU+2A03. The large bowl with a dot in it. It has no HTML name. In LaTeX the unicode-math package names it \bigcupdot.
⨄N-ary union operator with plusU+2A04. The large bowl with a plus in it: the big form of ⊎. ⨄ in HTML, \biguplus in LaTeX.
⩊Union beside and joined with unionU+2A4A. Two bowls side by side, joined at the rim. ⩊ in HTML.
⩅Union with logical orU+2A45. A bowl with a vee, the logical or, inside it. ⩅ in HTML.
⩁Union with minus signU+2A41. A bowl with a minus in it. Unicode also lists the name z notation bag subtraction.
⩂Union with overbarU+2A42. A bowl under a bar. ⩂ in HTML.
Union and intersection in one sign 4
⩉Intersection above bar above unionU+2A49. The same pair the other way up: ∩ on top, ∪ below the line. ⩉ in HTML.
⩇Intersection above unionU+2A47. An intersection stacked on a union. ⩇ in HTML.
⩈Union above bar above intersectionU+2A48. Union over intersection with a bar between them. ⩈ in HTML.
⩆Union above intersectionU+2A46. A union stacked on an intersection. ⩆ in HTML.
Square forms 5
⩎Double square intersectionU+2A4E. Two square caps, one inside the other.
⩏Double square unionU+2A4F. Two square cups nested the same way.
⨅N-ary square intersection operatorU+2A05. The large square cap, written before a family. In Unicode since version 3.2 (2002).
⨆N-ary square union operatorU+2A06. The large square cup, written before a family. ⨆ in HTML, \bigsqcup in LaTeX.
⊓Square capU+2293. Square cap, the intersection sign drawn with corners. ⊓ in HTML, \sqcap in LaTeX.
Not a set sign 2
ULatin capital letter UU+0055. A plain capital letter from the keyboard. The union sign is a character of its own, U+222A, and a search for one does not find the other.
nLatin small letter nU+006E. A plain small letter. Its arch looks like ∩, but the set sign is U+2229.