non-orientability
/ˌnɒnɔːrɪˌɛntəˈbɪlɪti/ /ˌnɒnɒrɪˌɛntəˈbɪlɪti/Mathematics
noun
The property of being non-orientable.
Origin
1930s; earliest use found in Proceedings of the National Academy of Sciences of the United States of America. From non- + orientability, after non-orientable.