substrate

An underlying layer; a substratum.

The substance lining the bottom edge of an enclosure.

The substrate of an aquarium can affect the water's acidity.

Stream substrate affects fish longevity.

A substance acted upon, as by an enzyme.

A surface on which an organism grows, or to which an organism or an item is attached.

The rock surface of a rockpool is the substrate for a sessile organism such as a limpet.

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.

A language that is replaced in a population by another language and that influences the language imposed on its speakers.

To strew or lay under.

The melted glass being supported by the substrated sand.

Having very slight furrows.