What is brand & product relevance?

Learned from book 'Brand Portfolio Strategy' by David A. Aaker page 103, relevance for a brand has two conditions. (not in exact words though..)

1. Perceived need or desire by customer for product category or subcategory defined by combination of attributes, application, user group, distinguishing characteristic
2. The brand is among the set considered by customer to be relevant for the product category or subcategory