(usu + to) to belong to somebody or something or exist as a part, attribute, feature, function, or right
He deplores the destruction and havoc pertaining to war
(also + to) to be appropriate
The criteria that pertain elsewhere do not apply here
formal (+ to) to have reference to something
She has shelves of books pertaining to birds
[Middle English perteinen via French from Latin pertinēre to reach to, belong, from per- + tenēre to hold]