What are breadcrumbs on a website?

Breadcrumbs are the small line of links printed above a page's title, showing the path from the home page down to the page you are reading. A shop selling rain jackets might show Home, then Outerwear, then Rain jackets, then the jacket itself. Every step except the last is a link, so its job is to tell you where you are and let you move up from there.

Search for a rain jacket, click a result, and you land deep inside an online shop on a single product. The breadcrumbs are the thin line above the product name reading Home, then Outerwear, then Rain jackets, then the jacket. Read left to right, that line names each level of the site above this page, and the last item is the page you are on, which is why it is plain text rather than a link. Click Rain jackets and you land on that group; click Outerwear and you go two levels up instead, so how far you travel depends on which step you pick. Why not just use the back button that every browser already has? Because back replays your own visit, which started at a search result, so it returns you to Google rather than into the shop, whereas this line describes the shop's layout no matter how you arrived. Two things follow. The layout it shows has to be the real one, since the hierarchy exists whether or not anyone prints it, and search engines pick up the same trail and sometimes show it under your result instead of the address.

Look at the folder path along the top of a file window: Documents, then Taxes, then 2025, then the receipt you opened. That path is not a record of what you clicked, and it reads the same whether you opened the folders one by one or searched the whole computer, because it describes where the file sits. Click 2025 and you are in that folder; click Taxes and you are one further up. Breadcrumbs are that path, printed on a web page, for the same reason.