zīˈgan.trəm, zə̇ˈ- noun
( plural zygan·tra -rə ; also zygantrums )
Etymology: New Latin, from zyg- + Late Latin antrum cavity of the body — more at antrum
: a fossa on the posterior median part of the neural arch of a vertebra (as of a snake) that accommodates the zygosphene of the next vertebra