From SuspireWiki

Knight is the Title of Function given to an oathsworn Soldier. A Knight is distinguished from a Soldier by membership in an established Order of Knighthood, with its own traditions and oaths of conduct. Membership in the Order of Knighthood replaces titles of esteem with Sir or Dame, for male and female Knights, respectively. The formal address is Sir Knight, or Dame Knight.

Notably, there is knight which has the lexicon description of: Any Kindred of the Invictus with a responsibility to engage in violence. A Kindred with a sworn oath to hurt or be harmed on behalf of a superior, whether landed or not.

While the Knight connotation has this definition: A knight whose sole or primary duty is to serve in combat. Any professionally militant Kindred who belongs to a Knightly Order. Any landed knight. (Historically, this term was reserved for knights with other Invictus titles, but modern nights have seen the term applied to sworn combatants of other covenants who fight on behalf of the Invictus as well.)