Definition of "substrate"

This definition [of "tool"] is not simple, but contains several elements. The tool must not be part of the animal's body (a beak is not a tool); the user must manipulate the tool in some way for it to realise its function; and, finally, a tool cannot be attached to the substrate. This is a fairly clear definition, but does seem to produce some rather arbitrary distinctions (Hansell 1987b). The spider Dinopis, for example, makes a small web which it holds in its legs, thrusting it down on passing ants. This is a tool, but all other webs, however complex, are not since they are anchored to the substrate. The woodpecker finch […] that uses a fine stick held in the beak to extract insect prey from wood, is a tool user, but a shrike […] that impales an insect on a thorn still attached to the bush is not.

2000, Mike Hansell, Bird Nests and Construction Behaviour, page 90

Detach/subtract [tasks involve] Severing a fixed attachment between environmental objects (or the substrate) or removing object(s) from another unattached object, so the latter is a more useful tool.

2006, Edward A. Wasserman, Thomas R. Zentall, Comparative Cognition: Experimental Explorations of Animal Intelligence, page 520

The melted glass being supported by the substrated sand.

1663, Robert Boyle, “(please specify the page)”, in Some Considerations Touching the Vsefulnesse of Experimental Naturall Philosophy, […], Oxford, Oxfordshire: […] Hen[ry] Hall printer to the University, for Ric[hard] Davis, part I