A logo is a mark: a specific visual element placed on a business card or a building sign. An identity system is the complete set of visual and verbal conventions that govern how an organisation presents itself across every context — the typefaces, the colours, the photography style, the written tone, the spacing around the mark, the way materials feel in the hand.
The logo is the most visible shorthand for the system. It is not the system itself. A logo without a system is a mark without governance: it can be applied consistently only while someone remembers how it should look. The moment institutional memory fades — a staff change, a new vendor, a different design resource — the mark begins to drift.

