Remembrance, remembrancer, reminder, memorial, memento, token, keepsake, souvenir denote something that serves to keep a person or thing in mind.
Remembrance and the less common remembrancer are applied to an object which causes one to call back to mind someone or something, especially someone dead or far away or an event or occurrence of the past, often the distant past.
Reminder suggests something (as a memorandum) that keeps one from forgetting; the term need not suggest a wish to remember.
Memorial suggests a wish or desire to preserve the memory of something (as a person or event) and therefore applies to a reminder (as a building, a monument, an endowment, or an observance) that is of a kind fitted to endure.
The remaining words more consistently suggest a personal association between the thing intended as a remembrance or reminder and the person, experience, or place to be remembered.
Memento typically applies to something small or trivial kept to satisfy a desire to renew the remembrance of some past interest; often the word suggests that the thing itself has no longer any value.
Token often refers to something treasured as a memento, but it usually denotes a gift presented to one as a sign of affection, esteem, or regret at parting.
Keepsake represents the attitude of the receiver rather than of the giver; otherwise it differs little in general use from token and memento .
But keepsake may apply specifically to a giftbook, often one made up for a particular group or occasion or as a specimen of fine printing.
Souvenir (see also MEMORY ) usually implies a material reminder not necessarily given nor received that remains or is kept as a memento (as of a place visited or of an experience worthy of remembrance).