Memorial, n.
Etymology: [Cf. F. mémorial.]
1. Anything intended to preserve the memory of a person or event; something which serves to keep something else in remembrance; a monument. Macaulay. Churches have names; some as memorials of peace, some of wisdom, some in memory of the Trinity itself. Hooker.
2. A memorandum; a record. [Obs. or R.] Hayward.
3. A written representation of facts, addressed to the government, or to some branch of it, or to a society, etc., -- often accompanied with a petition.
4. Memory; remembrance. [Obs.] Precious is the memorial of the just. Evelyn.
2 more senses
5. (Diplomacy)
A species of informal state paper, much used in negotiation.
1 other Webster entry under this spelling
Memorial, a.
1. Serving to preserve remembrance; commemorative; as, a memorial building. There high in air, memorial of my name, Fix the smooth oar, and bid me live to fame. Pope.
2. Contained in memory; as, a memorial possession.
3. Mnemonic; assisting the memory. This succession of Aspirate, Soft, and Hard, may be expressed by the memorial word ASH. Skeat. Memorial Day. Same as Decoration Day. [U.S.]
Shades of meaning
Fernald has no entry of its own for memorial; he lists it under history, record, trace.
Where he writes about it:
A memorial is any object, whether a writing, a monument, or other permanent thing that is designed or adapted to keep something in remembrance. — from record
Record is a word of wide signification, applying to any writing, mark, or trace that serves as a memorial giving enduring attestation of an event or fact; an extended account, chronicle, or history is a record; so, too, may be a brief inventory or memorandum; the inscription on a tombstone is a record of the dead; the striae on a rock-surface are the record of a glacier's passage. — from record
A memorial is that which is intended or fitted to bring to remembrance something that has passed away; it may be vast and stately. — from trace
On the other hand, a slight token of regard may be a cherished memorial of a friend; either a concrete object or an observance may be a memorial. — from trace