An honour whereby one is made into a knight, and one can thereafter be called "Sir" / The quality of being a knight. / The knights collectively, the body of knights.

plural of knighthood

An order which (at least mainly) consists of members who receive and/or most have the knighthood, hence constitutes an honorific brotherhood (in modern times often open to both genders, in rare cases a sisterhood) of knights (and/or, as female equivalent, dames). The hierarchical structure, purpose, activities (in many cases rare and mainly ceremonious), titles and insignia vary widely.

plural of order of knighthood