≅

≅

1. (mathematics) Approximately equal to.

   (The addition of quotations indicative of this usage is being sought:)

2. (geometry) Congruent to.
   • 2017, 專門用來打好幾何基礎的數學課本 [A mathematics textbook designed to build a good foundation in geometry], volume 1 (in Chinese), Wu-Nan Book Inc., →ISBN, page 95:

     如圖2.1-7，△ABC及△DEF兩三角形全等，△ABC ≅ △DEF。

     As shown in Figure 2.1-7, △ABC and △DEF are two congruent triangles, △ABC ≅ △DEF.

3. (algebra, category theory, logic) Isomorphic to.
   • 2011 May 5, Clive Reis, Abstract Algebra: An Introduction To Groups, Rings And Fields (in English), World Scientific Publishing Company, →ISBN, page 137:

     Suppose that G ≅ H. Then there exists an isomorphism f, say, from G to H.

• = (equal to)
• ∼
• ≆
• ≈
• ≃
• ≈ (almost equal to)