In the theory of 3-manifolds, a compression body is a kind of generalized handlebody.
A compression body is either a handlebody or the result of the following construction:
Let
S
S x [0,1]
S x \{1\}
Let
C
\partial-C
S x \{0\}
C
\partial-C=\emptyset
\partial+C
\partialC
There is a dual construction of compression bodies starting with a surface
S
S x \{0\}
\partial+C
S x \{1\}
\partial-C
\partialC
Compression bodies often arise when manipulating Heegaard splittings.